Hi Paul! I’m an EE and I’m not surprised at all that another EE would say that. I worked with several EEs who came out of school and although they knew the academics, they weren’t worth a crap in the field troubleshooting automated industrial equipment. I can remember asking one “How should we test this cable?” This cable was for a 250 amp DC power supply. You guessed it as an ohmmeter was his answer. Then I had to teach him about voltage drop testing which of course he never heard of. 👍
NEWS FLASH!! Ohmmeters will lie to you! Between flow charts written with an ohmmeter as the tool of choice and then people telling me "you should have measured resistance on that circuit, you are over-complicating things with your methods", I've seriously had enough! Time for everyone to learn something. Watch close and never tell me again to use an ohmmeter in a case like this. Here is the original video on CZcams Poor running, flashing CEL, no codes (bad computer ground) - Toyota czcams.com/video/44dP6X3QS5A/video.html Here is the SD Premium video I am recommending as a follow up www.scannerdanner.com/scannerdanner-premium-chapters/basic-electrical-concepts/485-basic-electrical-review-part-2.html
I am a retired mechanic of 36 years on the job. I started working on cars in 1980 the first year GM had computers in cars. I did a lot of electrical work and in the early years i was factory trained. I always checked a ground with a ohm meter. You teach me something in almost all of your videos, I wish there were more teachers like you when i was starting. Anyone going into this field of work should at least subscribe to your premium channel i would have went to your classes!!!!! Thank you so much for being you, you are the best teacher anyone could ask for.
If engineers had to fix the garbage they design today, things would get MUCH easier for us in the shop, that's for damn sure. GREAT explanation as always, Paul. Great to see Caleb absorbing all this knowledge, too. He's probably already a better diagnostic tech than I, and I've been doing this as long as I can remember. 😎
What I learned from u is good continuity does not mean good CONDUCTIVITY Check voltage drop of the circuit current has to flow A continuity test can’t verify the ability to handle the circuit current
I have proven to myself that the load pro works great for such occasions. Not advertising here but the darn thing works on my meter like a charm. I myself have used the ohm meter and misdiagnosed a simple problem. Spot on !!
I teach for a major auto manufacturer and we teach voltage drop. We even show where the resistance check will lie to you. It's all about the voltage drop or load testing.
Archie I took 2 of your electrical classes back in 2017 or 2018 and I remember you telling the class this. To this day your classes were some of the best training I've ever had
It’s always funny that people comment that you are wrong yet never make thier own content and believe they are right no matter what. This isn’t home wiring this is auto circuits. I bet the guys not even an engineer. Thanks for sharing Paul great job on this.
Totally agree. The other down side to Ohm checks is you have to isolate the circuit. Which means disconnecting stuff & ultimately changing the circuit. The Observer Effect at it's finest (the mere observation of a phenomenon inevitably changes that phenomenon). Sometimes simply touching the wires/connectors will 'fix' the problem, sending you down a rabbit hole and possibly never finding the problem. So if you can test the circuit with the circuit untouched, you will have a higher probability of success (and probably develop less gray hairs in the process).
Voltage Drop Testing is always the way to go. Dan Sullivan has been aware of this for many years. This is why he invented the LOADpro diagnostic tool. And this is why I bought one for myself. It's important to mention that you should always make sure that you have a fully charged battery and that all grounds are good and all your terminals and posts have been taken apart and cleaned and reinstalled. The same applies to the Battery Posts the Positive and Ground Cables as well looking for Corrosion and damaged cable insulation. The Voltage drop test will the level of Resistance in the circuit if any. Then you can investigate if the problem is on the Positive side or the ground side or is it simply a defective part that needs to be replaced. I am one of your loyal subscribers. 👍👍
That's awesome professor. It's a good feeling proving people wrong. I remember that case study u were talking about the 900 ohm of resistance on that GM vehicle with the aftermarket alarm system that the customer didn't even know was there. Great job professor. Cant wait for the navigator case study. Take care 😀
Using a test lead on your Power probe 4 . Go to Feed mode and touch those same points. The red or green Led will light up / annoying sound to let you know if you have a good ground or power etc...also you can read the resistance at the same time. It will not light up or sound off if there is high resistance. The PP4 will load the circuit internally like your test light. Great learning video 👍 you guys made
You teach what works best for you. The do it your selfers will have to make up their own minds. Just keep teaching mate. Knowledge is all we really have to keep. Your work is appreciated.
Paul (Not Dan) I am an avionics tech by trade. I have been working on airplanes and cars for nearly 35 years. This includes teaching basic avionics to new technicians at our airline. My automotive education started with a tach and dwell meter, and for diagnostics it was a Sun Interrogator and a Simpson 260 analog meter! What you are saying here (and so many of your videos) is spot on! Many of the fundamentals roll right into the aircraft electronics world as well. I have even had a few of my guys come have a look at this video specifically. I'll be buying your book as I have started to get into working on newer cars as a side business. You are doing awesome work!
Glad you taught that electrical engineer something valuable for free that he didn't learn in college. Keep up the great work and proven information doesn't lie. :)
GM teaches us how to do voltage drop, but really focuses on resistance measurements. I’ll do them on cars where I have no idea what’s going on and need to follow the flow chart (unfortunately) but your methods have really opened up my diagnostic abilities over the last year and I just wish I had more time to go through your stuff
I agree with you 100%. Problem is that ohm testing is still being taught to apprentices here in New Zealand, and probably many countries. The use of an incandescent test light is not allowed here in many workshops because of the damage they cause!! Their reasoning is beyond belief. I'm sure some instructors & techs still think the world is flat!
Hi SD. I'm also an EE and I was thinking, you can't get the required resolution using a simple ohmmeter to tell a bad ground. As you said, 30A through .1 ohms will show 3V of drop and anyone looking at .1 ohms would probably call it good.. Not to mention, the ohmmeter won't heat up a connection like current flow will. Agreed, voltage drop all the way.
I agree with your assessment that the resolution of the ohms meter isn't good enough. Paul, I'd love to see an experiment next time you run into one of these. Measure current as well as voltage drop on the bad connection. We could use ohms law to prove that there is measurable resistance there, the meter just isn't good enough to report it.
Hi Dan I live in the UK and have been doing diagnostics since the 70s, I did 25yrs for the RAC which is like your AAA but we have dedicated patrols who now have diagnostic readers so prior to that the training centre I ran/managed had nothing but good multimeters for years which give you a good grounding for using a diag tool, and the one thing we had on a sign in the workshop was "volt drop change my life" ,because exactly what you said you can get good resisstance on circuits, coils etc even when they are bad. Keep up the good work Ian
Nice reminder backed up with solid proof! I spent my first years as a tech scratching my head after completing resistance tests and results showed all was well when it wasn't! Loaded circuit voltage drop tests started finding faults quickly and put the joy back in the job!
I work at the Fiat Chrysler plant in Windsor Ontario Canada repairing the Dodge Caravan and the Chrysler Pacifica and I never use the ohm meter except to check camera functionality as this is the only way to check if the camera is good or not. I just uses the voltage drop method as it is by far the best way to check things. Thank for this video (and all your videos) as it helps people to understand this.
Garbage in Garbage out!.. load test/voltage drop test all power supplies. Fantastic video. The engineers are the ones that make these awful misleading flow charts.
I first learned about load testing and voltage drops from over on Daniel Sullivan’s channel. Changed my whole outlook on circuit diagnostics. Thanks to you to for a very clear and concise explanation on this and how there major differences.
GREAT INFO PAUL! I absolutely love love love the premium channel can't get enough of it you have taught me lots of valuable knowledge even for me being a heavy duty Diesel technician , It doesn't matter I work on literally everything. Appreciate all the hard work you put in these videos 👍🏼
This comment is awesome, thank you! Would you be willing to put this on my feedback page? Either way, it is so cool to hear how the material transcends the auto field (if that's the right wordl
I remember this video. Awesome example. I always try to remember we need to evaluate a problem while its happening instead of static measurements. You sir are the man
Haven’t finished watching this, but great point Paul. Basically it‘s like testing resistor in circuit on the PCB board. You can have reading 20ohm of 10kohm resistor. Does it mean that resistor broken? Of course no, it just act as a conductor, therefore until there are current it wont resist anything. Voltage drops and injecting some current are crucial things during troubleshooting electrical/electronic components of the car.
you guys are the best. now on with the show ❤️️ much easier to do a voltage drop test or computer ground test and leave the ohmmeter locked up. Thanks, Paul and Caleb
I totally remember that Toyota video..Lol. Great lesson on why voltage drop is best. Thanks for sharing this Paul. Great video.! Put that freaking Ohmmeter BACK in the toolbox.! 😂😂👍🍻 Cheers Brotha
ScannerDanner. I thank you. Your theory on chequing the voltage drop. Am not an electrician. I don't know why people who are experienced electricians. Can see the easy practicality of your sureshot tecnique. But it sure will make second guessing. Away with the useless time wasted. You're right on the money. Ohms quantity testing - Like you said on the engine grounds going to the computer. It's a waste. Unless you take your time to inspect the conditions for a solid ground. Going to the computer 💪💪. Always checking voltage drops. I would say. On every electrical problem is 🔑👍. Making sure the relay is okay every time.
Thank you thank you. Techs have to fix all bad engineering. Work for international dealer boy if the public can only see what they build. You would run the other way.
I agree some.u gotta think engineers cant think of every aspect of wat they design.its so many things that have to be factored in.do they say i wonder if i put this in this location would it be easy for the tech to repair.no.thats the reason why they r constantly changing things.its easy to blame them.those guys r brilliant.2 thats why they make more than us.
I agree. I believe you should know ohm testing on a fundamental level but should master the voltage drop testing. The times I’ve mostly used ohm testing is if I think I have an intermittent break in the wiring and I would use the graphing meter on each end of the wires and start wiggling the harness.
Watching every single video of yours. Wish i could have seen all your videos when you started your career. Absolutely awesome videos. Calib you are blessed to be part of your dads business. First hand info. Absolutely brilliant. Thank you very much. I am not a mechanic but do work on peoples cars. Absolutely brilliant. Luv everything. Cannot get enough of your info. You are helping so many people. Watching your video, then go to my toyota to do same tests where possible. 👏👏👏👏
With this attitude, you will succeed! Watch all the free ones here on CZcams, then come to my website if you want more. I have about 450 more video there with half of them classroom lectures where I invite you to be part of it online. www.scannerdanner.com/join-scannerdanner-premium.html
Absolutely agree. Loaded voltage drop test is the way to prove wire integrity. In the electrical field the utility workers have what they call "the beast". They clamp on at the meter and seriously load the service drop. If there is a weak connection you will see a voltage drop. I might add, even on a short to ground or ground fault i tend to grab my megohm tester. A gfci trouble call can be hard to trace with a wimpy ohmmeter. Put 500 volts and ground fault shows up easy. (Not for cars) love engineers but sometimes......a little experience goes a long way! Cheers
@@ScannerDanner lol. It will tickle. A bit like the spark plug. It's actually referred to as an insulation tester. Commonly used to test motor windings. In nj, we had to megtest wiring that had not been permitted. If a nail or staple knicked a wire this would show. My fluke 1507 can test @ 50,100,250,500, and 1000 volts. I imagine on a car you could fry stuff if not careful. Same precaution as welding on a car? Cheers
@@ScannerDanner a insulation resistance (megger tester) is commonly used for testing insulation resistance on high voltage motor windings etc. It applys a large voltage to the circuit and measures the current flow to provide a resistance measurement. Unfortunately they don't suit testing low voltage systems.
@@ScannerDanner I've heard you say it in other videos but the ohm meter is testing at very low voltage/current. The closer the test matches real conditions the better. So, yeah you hit the nail on the head. I plan on buying a test light asap. (From your friends JB) like you, i love an excuse to buy a new tool! Honestly, half the reason i love your channel is seeing all the cool tools! Cheers
Fantastic vid. I was working on a No Crank No Start on a Bobcat. I was convinced it was somewhere in the ignition wiring. My test light bulb was burned out and I had no spares. At the time, I didn't have a power probe. So I used my multimeter and checked the resistances instead of repairing my tool kit... shame on me. I wasted unneeded time. I eventually pulled my head from my butt and borrowed my friend's test light. I started my tests and checks all over again. I followed the voltage drop test all the way to a hidden damaged wire within a very inconvenient place in the frame that was being held together by a single strand of wire. That single strand was enough to positively test continuity but would drop the voltage.
freaking awesome, voltage drop for the win !!!!! Paul how dare they try to question your skills ??? good thing you showed them !!!!! hey buddy sign up for scannerdanner premium maybe you'll learn a thing or two lol !!!!!Paul for president 2020 !!!!!
A bad ground is like a kinked garden hose, an ohm meter is still going to show 0 ohms and voltage on a bad ground. Put a load on the bad ground and you will see the like kinked water hose, when the voltage is not there like the supplied voltage. nice video Mr Danner.
Agree with the voltage drop test! ScannerDanner Premium is money well spent as I have been a subscriber since the beginning and have been educated on many test procedures.
It is simple that an ohm meter doesn't provide enough load to a circuit to show a high resistance, a loaded test will show a fault where an ohm meter won't. Great work, Paul.
Great video Paul. As an automotive lecturer in colleges myself I regularly inherit learners/mechanics/apprentices with a sort of beginning knowledge of electrics in need of improving. This exact point - that the pittance of current pushed by a multimeter battery doesn't load the circuit, and therefore a terrible ground for example would 'pass' an ohmmeter test - is one we have to regularly cover. REPEATEDLY. :) The solutions are several - repeated examples (also I direct them to your book and vids as you know :) ); a revisited firmer command of the basics; simply getting them into the habit of saying "volt drop" not resistance sometimes helps a little too. The problem is that to a basic understanding their mistake (though still wrong) is based on 'correct' statements. So that bad ground for example. They have the following basics: "the problem could be too much resistance" "Resistance is measured in ohms" "An multimeter can measure ohms" and from those 'true' statements they draw the wrong conclusion "therefore a multimeter set on ohms can test this bad ground". To say to them "yes, in a sense the problem IS too much resistance...and I DO get WHY you would think that...but you can't test it by directly testing resistance per se like that." makes their brains hurt at first :) So as much as I (and eventually THEY too) understand why this is wrong...I do have some sympathy as I get WHY they make this basic error. BUT....That 'experienced mechanics/technicians get this wrong though...there's no excuse. And as for the 'electrical engineer' that had a go at you. ha. :)
Scanner danner is the man! 5 years out of trade school and still learning much more than shop foreman with 15 years in one make can show. Premium is on your website correct?
awesome video, I preach this whenever I diagnose the issues that the other techs in my company fail to figure out and have reached the end of THEIR rope, ohm meter readings will say yea its good at this low current level but the real situation is revealed when you put the pedal to the metal and look at what's going on while real operating conditions are in play.
The EE's flow charts don't Stress, Load, or Strain the wires in question as you have by turning the key ON, and pressurizing the circuits to their normal capacity, to "catch" excessive drops in voltage with Ground- to-Ground voltage drop checks. I've heard it called 'stealing" voltage from the circuit, which in your case was the corrosion . I hope this makes your case stronger!!
He did and to be fair he was not being a d-ick in anyway. It just struck a nerve for me because he quoted exactly what a manufacturer flow chart would have you do.
Hi SD. Think it could be my comment you refer to in this vid, i`m so pleased and impressed that you made this one to clear up the guidance of the previous. Yes of course we can use a scope, which i would suggest is maybe a piece of equipment that a lot of people don`t have available to observe diff characteristics but in that demonstration you were utilising a lamp which for me is vague indicator. What i was aiming to suggest is that a loop resistance test is far better than the brightness of a lamp as a means of analysis and yes i could have suggested a voltage drop test of some sort. Thank you, i remain a big supporter of your information and guides and was merely attempting to add guidance as opposed to criticise. I meant well.
I'm so sorry to have jumped all over that comment the way I did. I want you to know that my seemingly extreme reaction to your suggestion had some very personal and real build up frustrations about how things are taught in my field, over a very, very long time and the comment just struck a nerve and reminded me that I needed to do this. As for the test light test I showed in that AC clutch video, in particular the ground to ground test, I wasn't so much looking for or at the brightness of the bulb, but only to show that it wasn't lit at all, while the compressor had power, proving and open ground was NOT the cause. As you probably know, an open ground in that scenario would have lit my test light. Then I believe I switched my light to battery positive, showing the light was lit the whole time and I mentioned that this test was not valid unless the circuit being tested was also turned on (I believe I used the word energized). My point there was a partially bad ground may light my test light but when you apply circuit load, that partially bad ground would heat up, causing a resistance rise and a dim test light. So one can absolutely use the test light in a non loaded, then loaded situation and compare. Hope that makes sense. As for the scope being shown in this video, it was simply a voltmeter. Sure I had a waveform, but a voltmeter would have shown you the 3-4 volt average on that bad ground and that was the point. A voltage drop test is the way to handle this, not a resistance test. Again, I'm sorry that I went off like I did and I respect you so much for your reaction to my rant.
Hi SD, i thank you so much for your clarification here in this comment. I think i understand completely where you are coming from in your point of view about your trade teachings and striking a nerve with you personally, i can detect that you went out of your way to make this latest presentation therefore it appeared to me to be a very important subject matter to you yourself, actually thought the presentation content was brilliant. My training as electronics engineer started oh about 40 years ago as a TV engineer and have since that time also had a natural interest in cars where electronics knowledge has been invaluable although i do realise that diagnosis in your field is different so the process of finding a fault has to be suitable to the environment. Really enjoy your presentations, you have a great way of getting your information across and think you have some wonderful knowledge. I remain a big fan. Tony
Thanks man. I promise to not bash the engineers so much in the future. There is a broken system from the top down that doesn't necessarily lay blame on the guy writing the flow chart.
Thanks SD, really appreciate your feedback and look forward to you showing us a better way to get the right diagnosis done maybe one day even on a Mazda 2 which i drive and have an odd problem with. Tony
Great video! I never had to follow what a manufacturer was telling me because I've learned the correct testing procedure from Paul Danner and other great diagnostic CZcams channels! 👍
Another excellent video...Thanks!!! It's like one of those movies you need to watch multiple times... Working with circuit boards, so often I see where the power looks just like that jittery wave of your ground in the video (almost always a cold solder joint)...I'd say 75% of most circuit board failure issues are power-related (and often mechanical in nature)... Forget about it...considering the load of a measuring device?....Make everyone cry. Thanks again.
I got "burned" a little using the DVM a few months ago fixing my horn circuit problem on the 1999 Silverado; the test light came to the rescue and proved I was chasing a ghost..
Great info dude! You’re right about flow charts using an ohm meter for testing, but when I go to Honda training (I’m an Acura dealer tech), they really push voltage drop testing now. So factory training is doing the right thing at least. I view flow charts as more of a guide 😆
You’re a badass man!! I hear a lot of people saying you’ve changed their life in diagnostics. I wanna better myself in diagnostics. So guess whos joining your class? 🙋♂️🙋♂️
Dan Sullivan the guy who invented the load pro test leads, would always say in his videos that the problem is usually something simple. Case in point you found a corroded grounding spot on the engine block. The diagnosis may take some time, but the solution is something so simple.
I've seen voltage drops in battery cranking and charging grounds. One shop couldn't understand why they were changing batteries (2) in a large truck. Battery ground was at a steel plate less than 1 foot from the battery. The steel was part of a steel body bolted to the truck frame, and there was a large flex ground jumper from the frame to the engine. One new triple ought (000) cable from the battery Negative to the engine block and a 2.6 Volt voltage drop went to .7 drop during cranking. No more battery, cranking and charging problems!
The health of a circuit can only be determined when it's capable of flowing the designed current at the designed voltage. Makes total sense really. No one builds a circuit for the end-result of a resistance specification. The whole purpose of a circuit is to carry a specified current at a specified voltage.
I was testing a GM air conditioner system on an S10. I had power everywhere it was supposed to be, had ground too. Circuit still failed to operate when i plugged everything back in. I switched to a test light and checked my meter, power, when i touched test light it dropped to "0". All became clear, LOAD THE CIRCUIT!! It was a bad relay, burned contacts the post mortem revealed. So i am absolutely on board. I have also discovered that electrical engineers generally go by the mantra "looks good on paper", as we know, in reality outside the draft board, its all very different.
Many good points here and I'll make a point too. Comparing a low cost/accuracy multimeter to a high cost/accuracy scanner/oscilloscope isn't fair. And I'm with you on volt drop testing too.
it wasn't about a low cost meter. You could have used a fluke ohmmeter and it would have given you the same results. It was about the ohm test being a b.s. test in most automotive applications, yet that is what the manufacturer flow charts are full of. Ohm tests...or I should say b.s. 😂😂
Awesome example of what you could be missing, this is the kind of stuff with an ohm meter that would cause head scratching and possibly replacement of an part that was good.
Current handling wire and connections with dissimilar metals & corrosion will get you over time; happens all the time with aging "stuff"; more so in the "salt belt" areas of the country.
Since this is the latest video, I hope Mr. Danner gets to see this question which is perhaps more of an opinion. Furthermore, I hope he forgives the long post. My second profession before I retired had been working as an electrical contractor. Mainly in residential and office building market. The electrical system in a residential unit consists of three wires that come to the top of the house electrical panel and a GROUND wire that usually comes out of the bottom of the panel. This heavy wire connects to the house cold water pipes that are buried in the street (ground) and usually an eight (8) foot solid copper rod that is driven into ground. Called ground rod. Basically, the purpose of the ground system is to protect an occupant should a live wire touches the body of an appliance. The ground wire in an outlet or appliance, routes the live voltage to “ground” rather than the body of an occupant. Thus, preventing a heart attack. Now the reason for this post---I know I am probably going against many years of automotive electrical charts and training books, so bear with me. Why a body of an automobile is called “ground”? There is no connection between the vehicles body and the earth. Rubber tires prevent an electrical connection. In a simplified DC circuit; in order for any circuit to work, it requires a path for 12V positive to reach the load. It also needs a path of return to 12V negative, which are the two terminals on the battery. The automotive engineers figured that since there is metal in the frame and body of the powertrain, it would save wire (money) to use the frame as the path for negative voltage to battery. That is a great idea, but why call it “ground”? Why not call it chassis? After all the negative wire of the battery is connected to the chassis of an automobile. Anything, but “ground” makes more sense in a DC system.
I use an ohm meter quite often for things such as verifying I have the wire I want or that a bulb is good but for checking the integrity of a circuit I’ve used voltage drop tests for years in both automotive and aviation. An ohm meter just doesn’t produce enough current to identify a less then perfect ground or wire integrity.
I use voltage drop testing a lot of the time to pin point or get a general idea of where the break in the wire is or where the corrosion is. I really like to load test, I built a small load bank that can draw about 11 amps at 12.6VDC, you can draw in .5 amp increments on 4 switches and 1 amp increments on 4 more switches. It displays voltage on the circuit and the amount of current you are drawing. I see ohm meters get guys in trouble all the time. Manufacture troubleshooting sucks most of the time. It will lead you down a rabbit hole if you are not careful, and you will not recover your labor from them instructing you to basically misdiagnose it. I have spoke to a couple of the manufactures that my shop deals with and they more or less scoff at me when I bring up the use of oscilloscopes or dynamic circuit testing. "You can't do that you are going to damage our product!" Maybe, if you don't know what you are doing. I have never cooked a board, but I have diagnosed and repaired a lot of things that troubleshooting trees have missed. Love your videos man, you putting out good information makes us all better techs.
Another great video ohm meters and resistant testing has its place and you are right high current wires need voltage drop testing will I don’t use your test lite method I do amp testing of the Circuit and yes only with the modules disconnected and after studying the diagram I check to see if the circuit can handle at least 10amps today’s vehicles uses more modules to control everything and electrical engineers really do not deal with corrosion , chafed wires and bad repairs to the wiring like we do Ps I have seen a signal like the one in these video but it was not a bad ground it was a bad alternator diodes pushing a/c in to the electrical system it’s funny what havoc a/c voltage plays on this systems lol
Load Pro works, but it is not the "end all" tool. I have had cases with resistance the load pro didn't detect. Happened to me recently on a BMW with a loose ground cable.
Great video Scanner Danner. Voltage drops test is the only way to go.thanks for all your amazing videos your a very sharp tech an trainer. I call my test light a scope on a rope.
Paul I attribute this to the fact that many do not understand the fundamental relationships contained within the confines Ohms' Law. And if we do not understand the solid ground of those relationships then our understanding of Kirchhoff's' Laws are built on sinking sand.
if it's a bundled ground and the car isn't running the load may not be right and voltage drop could be wrong. always make sure the circuit is loaded properly or heavily! yeah, repeating what you said more or less, people always forget that ;)
0:51 not to make fun of the engineer or all engineers in general, i(FNG as a dealer tech) had a 15 sienna come in for a no-a/c complaint, found out it has a code for the clutch lock-up circuit(essentially something that sends the signal to the computer to request a/c operation) well this vehicle had a new clutch-coil put on at the previous toyota dealer(out of state, why they put a clutch-coil on i dont know but thats what they did) but its still not working, fixed the pin fitment issue that it had in the circuit but it still didnt work, so now i(the FNG) took out my ohm meter and said well the coil has 200ohms(it was right in the middle of spec) of resistance so it must be good, take a closer look and you will notice the wires were not routed correctly so now did i just measure the resistance of my pulley? new clutch coil and it works now, ENGINEERS! WE LIVE IN THE REAL WORLD! resistence measurement is not always the way to go, i personally try to use a test light(kinda like what SMA made in a video) but ill use the peanut bulb for circuit integrity to check my wires, im sure i will get a lot of hate for this comment edit: curious how bright/dim the test light would have been in that computer ground before the fix, thanks again for the great content!!
I just had a great idea coming from the HVAC business 90% of technicians do not know how to use a multi meter or ampclamp Why don’t you try doing some videos on HVAC equipment troubleshooting I bet you get one hell of a response good luck
ScannerDanner Yes testing residential HVAC components using a multi meter and amp clamp also troubleshooting you could have a whole Nother career path believe me
What do you do on a car that randomly stalls? Dealer had had it for 2 weeks, no stall. I will take it home and 2 or 3 days later it will stall. Usually happens on a very hot day with a/c on. Never has a fault code.
I would turn the job down lol. But seriously, you would need test equipment hooked up and make it your everyday car with a list of checks to do for each stall and wait 3 days for the next one? See what I mean? No thanks. Need to break it more first then bring it to me. I can't drive customers cars around like that.
@@ScannerDanner in other words, sell the damn thing (i would tell the prospective new owner it has that issue). Thanks. I really do understand. Sad thing, it is a 2005 trailblazer with 50k miles and looks and drives (when it does) like a new car. Oh well, sometimes a low mileage car is worse than a high mileage one. Love your channel.
Start doing some common failure searches, this can narrow down the area of where to start testing, then get it to do it more often. Do the tests yourself and use my forum. It's free to join. Start with a throttle body cleaning and relearn then go from there.
I'm also an engineer and I say use an ohm meter Danner cause does what my tech manual says!!!ohh and I confirmed that with my poodle and she suggested the same thing.
Hi Paul! I’m an EE and I’m not surprised at all that another EE would say that. I worked with several EEs who came out of school and although they knew the academics, they weren’t worth a crap in the field troubleshooting automated industrial equipment. I can remember asking one “How should we test this cable?” This cable was for a 250 amp DC power supply. You guessed it as an ohmmeter was his answer. Then I had to teach him about voltage drop testing which of course he never heard of. 👍
NEWS FLASH!! Ohmmeters will lie to you!
Between flow charts written with an ohmmeter as the tool of choice and then people telling me "you should have measured resistance on that circuit, you are over-complicating things with your methods", I've seriously had enough!
Time for everyone to learn something. Watch close and never tell me again to use an ohmmeter in a case like this.
Here is the original video on CZcams
Poor running, flashing CEL, no codes (bad computer ground) - Toyota czcams.com/video/44dP6X3QS5A/video.html
Here is the SD Premium video I am recommending as a follow up
www.scannerdanner.com/scannerdanner-premium-chapters/basic-electrical-concepts/485-basic-electrical-review-part-2.html
Nice video. Drives me crazy when techs say they ohmed the wires! Load it up and check the voltage!!
Honestly it wasn't my intent the bash him in particular it was just the motivation I needed to touch on a very misunderstood concept.
Keep doing what your doing we love your teaching scanner danner screw the engineers
I see same with the power pro super heros
Fantastic demonstration of voltage drop testing Paul!
yeah, this one has been around for awhile and I keep referring people to the original video, but I cut it down to the main point :-)
Thanks Dan!
Hey dan when will you upload your video i am waiting for lots of excitement
Danny and Paul my idols.
DiagnoseDan's video coming
I am a retired mechanic of 36 years on the job. I started working on cars in 1980 the first year GM had computers in cars. I did a lot of electrical work and in the early years i was factory trained. I always checked a ground with a ohm meter. You teach me something in almost all of your videos, I wish there were more teachers like you when i was starting. Anyone going into this field of work should at least subscribe to your premium channel i would have went to your classes!!!!! Thank you so much for being you, you are the best teacher anyone could ask for.
Thank you Rick!
If engineers had to fix the garbage they design today, things would get MUCH easier for us in the shop, that's for damn sure.
GREAT explanation as always, Paul. Great to see Caleb absorbing all this knowledge, too. He's probably already a better diagnostic tech than I, and I've been doing this as long as I can remember. 😎
What I learned from u is good continuity does not mean good CONDUCTIVITY Check voltage drop of the circuit current has to flow A continuity test can’t verify the ability to handle the circuit current
I have proven to myself that the load pro works great for such occasions. Not advertising here but the darn thing works on my meter like a charm.
I myself have used the ohm meter and misdiagnosed a simple problem.
Spot on !!
Ralf; which load pro is a good one to get ? Thanks.
@@tubetime39 I'm sure they are all good I got the Original.
I teach for a major auto manufacturer and we teach voltage drop. We even show where the resistance check will lie to you. It's all about the voltage drop or load testing.
awesome! now go tell the manufacture higher ups to stop producing flow charts with resistance measurements for main powers and grounds :-)
Archie I took 2 of your electrical classes back in 2017 or 2018 and I remember you telling the class this. To this day your classes were some of the best training I've ever had
@@jharrison6557 thank you for the kind words
It’s always funny that people comment that you are wrong yet never make thier own content and believe they are right no matter what. This isn’t home wiring this is auto circuits. I bet the guys not even an engineer. Thanks for sharing Paul great job on this.
Totally agree. The other down side to Ohm checks is you have to isolate the circuit. Which means disconnecting stuff & ultimately changing the circuit. The Observer Effect at it's finest (the mere observation of a phenomenon inevitably changes that phenomenon). Sometimes simply touching the wires/connectors will 'fix' the problem, sending you down a rabbit hole and possibly never finding the problem. So if you can test the circuit with the circuit untouched, you will have a higher probability of success (and probably develop less gray hairs in the process).
Yup SD premium changed my life. Well worth every cent. Highly recommend 👍🏻
Thank you Burt!
Me too man! Money well spent.
Voltage Drop Testing is always the way to go.
Dan Sullivan has been aware of this for many years. This is why he invented the LOADpro diagnostic tool. And this is why I bought one for myself.
It's important to mention that you should always
make sure that you have a fully charged battery and that all grounds are good and all your terminals and posts have been taken apart and cleaned and reinstalled.
The same applies to the Battery Posts the Positive and Ground Cables as well looking for Corrosion and damaged cable insulation.
The Voltage drop test will the level of Resistance in the circuit if any. Then you can investigate if the problem is on the Positive side or the ground side or is it simply a defective part that needs to be replaced.
I am one of your loyal subscribers. 👍👍
That's awesome professor. It's a good feeling proving people wrong. I remember that case study u were talking about the 900 ohm of resistance on that GM vehicle with the aftermarket alarm system that the customer didn't even know was there. Great job professor. Cant wait for the navigator case study. Take care 😀
Your diagnostic videos are second to none. You are a fantastic teacher.
thank you JB!
Using a test lead on your Power probe 4 . Go to Feed mode and touch those same points. The red or green Led will light up / annoying sound to let you know if you have a good ground or power etc...also you can read the resistance at the same time. It will not light up or sound off if there is high resistance. The PP4 will load the circuit internally like your test light. Great learning video 👍 you guys made
The PP4 mode you are describing only loads the circuit with a less than 20 ma LED bulb. It too would have failed this test
You teach what works best for you. The do it your selfers will have to make up their own minds. Just keep teaching mate. Knowledge is all we really have to keep. Your work is appreciated.
@@foobarmaximus3506 Would you stop? Just stop.
Paul (Not Dan) I am an avionics tech by trade. I have been working on airplanes and cars for nearly 35 years. This includes teaching basic avionics to new technicians at our airline. My automotive education started with a tach and dwell meter, and for diagnostics it was a Sun Interrogator and a Simpson 260 analog meter! What you are saying here (and so many of your videos) is spot on! Many of the fundamentals roll right into the aircraft electronics world as well. I have even had a few of my guys come have a look at this video specifically. I'll be buying your book as I have started to get into working on newer cars as a side business. You are doing awesome work!
Thanks so much! I really like hearing how the info rolls into other fields. This means a lot
Paul, Caleb, I want to thank you two for providing such great online education, YOU TWO ROCK! (Netherlands Europa) 20:30 EST
Glad you taught that electrical engineer something valuable for free that he didn't learn in college.
Keep up the great work and proven information doesn't lie. :)
GM teaches us how to do voltage drop, but really focuses on resistance measurements. I’ll do them on cars where I have no idea what’s going on and need to follow the flow chart (unfortunately) but your methods have really opened up my diagnostic abilities over the last year and I just wish I had more time to go through your stuff
It's there when you're ready :-) you never miss a class
Yes,we like Paul's class
Excellent! So thankful a Chrysler training instructor recommended me to your channel! Time to level up my diagnostic skills from a true Pro!
Great to hear! Welcome!
I agree with you 100%. Problem is that ohm testing is still being taught to apprentices here in New Zealand, and probably many countries. The use of an incandescent test light is not allowed here in many workshops because of the damage they cause!! Their reasoning is beyond belief. I'm sure some instructors & techs still think the world is flat!
Thank you Paul Danner for doing what you do .Please keep keeping on brother !!!!!!
Nice
Hi SD. I'm also an EE and I was thinking, you can't get the required resolution using a simple ohmmeter to tell a bad ground. As you said, 30A through .1 ohms will show 3V of drop and anyone looking at .1 ohms would probably call it good.. Not to mention, the ohmmeter won't heat up a connection like current flow will. Agreed, voltage drop all the way.
I agree with your assessment that the resolution of the ohms meter isn't good enough. Paul, I'd love to see an experiment next time you run into one of these. Measure current as well as voltage drop on the bad connection. We could use ohms law to prove that there is measurable resistance there, the meter just isn't good enough to report it.
Hi Dan I live in the UK and have been doing diagnostics since the 70s, I did 25yrs for the RAC which is like your AAA but we have dedicated patrols who now have diagnostic readers so prior to that the training centre I ran/managed had nothing but good multimeters for years which give you a good grounding for using a diag tool, and the one thing we had on a sign in the workshop was "volt drop change my life" ,because exactly what you said you can get good resisstance on circuits, coils etc even when they are bad. Keep up the good work Ian
Best driveability teacher. Makes sense always
Nice reminder backed up with solid proof!
I spent my first years as a tech scratching my head after completing resistance tests and results showed all was well when it wasn't! Loaded circuit voltage drop tests started finding faults quickly and put the joy back in the job!
I work at the Fiat Chrysler plant in Windsor Ontario Canada repairing the Dodge Caravan and the Chrysler Pacifica and I never use the ohm meter except to check camera functionality as this is the only way to check if the camera is good or not. I just uses the voltage drop method as it is by far the best way to check things. Thank for this video (and all your videos) as it helps people to understand this.
Garbage in Garbage out!.. load test/voltage drop test all power supplies. Fantastic video. The engineers are the ones that make these awful misleading flow charts.
I first learned about load testing and voltage drops from over on Daniel Sullivan’s channel. Changed my whole outlook on circuit diagnostics. Thanks to you to for a very clear and concise explanation on this and how there major differences.
GREAT INFO PAUL! I absolutely love love love the premium channel can't get enough of it you have taught me lots of valuable knowledge even for me being a heavy duty Diesel technician , It doesn't matter I work on literally everything.
Appreciate all the hard work you put in these videos 👍🏼
This comment is awesome, thank you! Would you be willing to put this on my feedback page? Either way, it is so cool to hear how the material transcends the auto field (if that's the right wordl
@@ScannerDanner done!
I remember this video. Awesome example. I always try to remember we need to evaluate a problem while its happening instead of static measurements. You sir are the man
Haven’t finished watching this, but great point Paul. Basically it‘s like testing resistor in circuit on the PCB board. You can have reading 20ohm of 10kohm resistor. Does it mean that resistor broken? Of course no, it just act as a conductor, therefore until there are current it wont resist anything. Voltage drops and injecting some current are crucial things during troubleshooting electrical/electronic components of the car.
you guys are the best. now on with the show ❤️️ much easier to do a voltage drop test or computer ground test and leave the ohmmeter locked up. Thanks, Paul and Caleb
I totally remember that Toyota video..Lol. Great lesson on why voltage drop is best. Thanks for sharing this Paul. Great video.!
Put that freaking Ohmmeter BACK in the toolbox.! 😂😂👍🍻
Cheers Brotha
ScannerDanner. I thank you.
Your theory on chequing the voltage drop. Am not an electrician. I don't know why people who are experienced electricians. Can see the easy practicality of your sureshot tecnique. But it sure will make second guessing. Away with the useless time wasted. You're right on the money. Ohms quantity testing - Like you said on the engine grounds going to the computer. It's a waste. Unless you take your time to inspect the conditions for a solid ground. Going to the computer 💪💪. Always checking voltage drops.
I would say. On every electrical problem is 🔑👍.
Making sure the relay is okay every time.
Engineers is the reason why techs exist. Techs repair what engineers got wrong.
Frank Gonzalez I couldn’t agree more. It seems like certain Engineers would jump over 100 virgins just to screw a tech.
Thank you thank you. Techs have to fix all bad engineering. Work for international dealer boy if the public can only see what they build. You would run the other way.
I agree some.u gotta think engineers cant think of every aspect of wat they design.its so many things that have to be factored in.do they say i wonder if i put this in this location would it be easy for the tech to repair.no.thats the reason why they r constantly changing things.its easy to blame them.those guys r brilliant.2 thats why they make more than us.
I agree. I believe you should know ohm testing on a fundamental level but should master the voltage drop testing. The times I’ve mostly used ohm testing is if I think I have an intermittent break in the wiring and I would use the graphing meter on each end of the wires and start wiggling the harness.
Watching every single video of yours. Wish i could have seen all your videos when you started your career. Absolutely awesome videos. Calib you are blessed to be part of your dads business. First hand info. Absolutely brilliant. Thank you very much. I am not a mechanic but do work on peoples cars. Absolutely brilliant. Luv everything. Cannot get enough of your info. You are helping so many people. Watching your video, then go to my toyota to do same tests where possible. 👏👏👏👏
With this attitude, you will succeed! Watch all the free ones here on CZcams, then come to my website if you want more. I have about 450 more video there with half of them classroom lectures where I invite you to be part of it online. www.scannerdanner.com/join-scannerdanner-premium.html
Absolutely agree. Loaded voltage drop test is the way to prove wire integrity. In the electrical field the utility workers have what they call "the beast". They clamp on at the meter and seriously load the service drop. If there is a weak connection you will see a voltage drop. I might add, even on a short to ground or ground fault i tend to grab my megohm tester. A gfci trouble call can be hard to trace with a wimpy ohmmeter. Put 500 volts and ground fault shows up easy. (Not for cars) love engineers but sometimes......a little experience goes a long way! Cheers
What's a mega ohm tester? Awesome! Sounds like the tester alone could kill you?
@@ScannerDanner lol. It will tickle. A bit like the spark plug. It's actually referred to as an insulation tester. Commonly used to test motor windings. In nj, we had to megtest wiring that had not been permitted. If a nail or staple knicked a wire this would show. My fluke 1507 can test @ 50,100,250,500, and 1000 volts. I imagine on a car you could fry stuff if not careful. Same precaution as welding on a car? Cheers
@@ScannerDanner a insulation resistance (megger tester) is commonly used for testing insulation resistance on high voltage motor windings etc. It applys a large voltage to the circuit and measures the current flow to provide a resistance measurement. Unfortunately they don't suit testing low voltage systems.
That's still an awesome tool for you guys for sure.
@@ScannerDanner I've heard you say it in other videos but the ohm meter is testing at very low voltage/current. The closer the test matches real conditions the better. So, yeah you hit the nail on the head. I plan on buying a test light asap. (From your friends JB)
like you, i love an excuse to buy a new tool! Honestly, half the reason i love your channel is seeing all the cool tools! Cheers
Fantastic vid. I was working on a No Crank No Start on a Bobcat. I was convinced it was somewhere in the ignition wiring. My test light bulb was burned out and I had no spares. At the time, I didn't have a power probe. So I used my multimeter and checked the resistances instead of repairing my tool kit... shame on me. I wasted unneeded time. I eventually pulled my head from my butt and borrowed my friend's test light. I started my tests and checks all over again. I followed the voltage drop test all the way to a hidden damaged wire within a very inconvenient place in the frame that was being held together by a single strand of wire. That single strand was enough to positively test continuity but would drop the voltage.
100% my friend, good job!
Resistance testing is almost useless on any circuit that carries measurable current
freaking awesome, voltage drop for the win !!!!! Paul how dare they try to question your skills ??? good thing you showed them !!!!! hey buddy sign up for scannerdanner premium maybe you'll learn a thing or two lol !!!!!Paul for president 2020 !!!!!
#Trump2020. Paul for 2024
A bad ground is like a kinked garden hose, an ohm meter is still going to show 0 ohms and voltage on a bad ground. Put a load on the bad ground and you will see the like kinked water hose, when the voltage is not there like the supplied voltage. nice video Mr Danner.
Agree with the voltage drop test! ScannerDanner Premium is money well spent as I have been a subscriber since the beginning and have been educated on many test procedures.
Thank you!
You are one of the best, and you are very humble and down to earth.
i have never trusted ohm tests on circuits like this one, i have been caught out by this in the early years, another great vid mr danner.
Only can use ohm meter on airbag systems.
Older hondas ignition coils show perfect ohms but a no start. Replace coil starts right up
It is simple that an ohm meter doesn't provide enough load to a circuit to show a high resistance, a loaded test will show a fault where an ohm meter won't. Great work, Paul.
Thanks Jake
Great video Paul. As an automotive lecturer in colleges myself I regularly inherit learners/mechanics/apprentices with a sort of beginning knowledge of electrics in need of improving. This exact point - that the pittance of current pushed by a multimeter battery doesn't load the circuit, and therefore a terrible ground for example would 'pass' an ohmmeter test - is one we have to regularly cover. REPEATEDLY. :)
The solutions are several - repeated examples (also I direct them to your book and vids as you know :) ); a revisited firmer command of the basics; simply getting them into the habit of saying "volt drop" not resistance sometimes helps a little too. The problem is that to a basic understanding their mistake (though still wrong) is based on 'correct' statements.
So that bad ground for example. They have the following basics: "the problem could be too much resistance" "Resistance is measured in ohms" "An multimeter can measure ohms" and from those 'true' statements they draw the wrong conclusion "therefore a multimeter set on ohms can test this bad ground". To say to them "yes, in a sense the problem IS too much resistance...and I DO get WHY you would think that...but you can't test it by directly testing resistance per se like that." makes their brains hurt at first :) So as much as I (and eventually THEY too) understand why this is wrong...I do have some sympathy as I get WHY they make this basic error. BUT....That 'experienced mechanics/technicians get this wrong though...there's no excuse. And as for the 'electrical engineer' that had a go at you. ha. :)
Scanner danner is the man! 5 years out of trade school and still learning much more than shop foreman with 15 years in one make can show. Premium is on your website correct?
That is correct. Thank you so much! I look forward to hearing more form you on the site.
awesome video, I preach this whenever I diagnose the issues that the other techs in my company fail to figure out and have reached the end of THEIR rope, ohm meter readings will say yea its good at this low current level but the real situation is revealed when you put the pedal to the metal and look at what's going on while real operating conditions are in play.
The EE's flow charts don't Stress, Load, or Strain the wires in question as you have by turning the key ON, and pressurizing the circuits to their normal capacity, to "catch" excessive drops in voltage with Ground- to-Ground voltage drop checks. I've heard it called 'stealing" voltage from the circuit, which in your case was the corrosion . I hope this makes your case stronger!!
Really appreciate ur vids man , honestly I’ve learnt so much for ur content it’s made me a much much better tech
Thank you!
Great job Paul. I’ve tried to convince my coworkers that voltage drop testing is more reliable but it falls on deaf ears.
Mike
👍glad there's teachers like you keeping things real world. Hope to be part of the premium channel some day. Just too busy now. Thanks!
Thanks James!
I’m curious if this EE went on to explain how he would prove a bad ground with just his ohmmeter???
He did and to be fair he was not being a d-ick in anyway. It just struck a nerve for me because he quoted exactly what a manufacturer flow chart would have you do.
Great video Paul and nicely explained.
Voltage drop testing all the way!
From Nick Ayivor from London England UK 🇬🇧 ⏰ 23.47pm 21,04,2022
Thank you very much 👍
SUBSTANTIAL Sir ScannerDanner
Hi SD. Think it could be my comment you refer to in this vid, i`m so pleased and impressed that you made this one to clear up the guidance of the previous. Yes of course we can use a scope, which i would suggest is maybe a piece of equipment that a lot of people don`t have available to observe diff characteristics but in that demonstration you were utilising a lamp which for me is vague indicator. What i was aiming to suggest is that a loop resistance test is far better than the brightness of a lamp as a means of analysis and yes i could have suggested a voltage drop test of some sort. Thank you, i remain a big supporter of your information and guides and was merely attempting to add guidance as opposed to criticise. I meant well.
I'm so sorry to have jumped all over that comment the way I did. I want you to know that my seemingly extreme reaction to your suggestion had some very personal and real build up frustrations about how things are taught in my field, over a very, very long time and the comment just struck a nerve and reminded me that I needed to do this.
As for the test light test I showed in that AC clutch video, in particular the ground to ground test, I wasn't so much looking for or at the brightness of the bulb, but only to show that it wasn't lit at all, while the compressor had power, proving and open ground was NOT the cause. As you probably know, an open ground in that scenario would have lit my test light.
Then I believe I switched my light to battery positive, showing the light was lit the whole time and I mentioned that this test was not valid unless the circuit being tested was also turned on (I believe I used the word energized).
My point there was a partially bad ground may light my test light but when you apply circuit load, that partially bad ground would heat up, causing a resistance rise and a dim test light. So one can absolutely use the test light in a non loaded, then loaded situation and compare. Hope that makes sense.
As for the scope being shown in this video, it was simply a voltmeter. Sure I had a waveform, but a voltmeter would have shown you the 3-4 volt average on that bad ground and that was the point. A voltage drop test is the way to handle this, not a resistance test.
Again, I'm sorry that I went off like I did and I respect you so much for your reaction to my rant.
Hi SD, i thank you so much for your clarification here in this comment. I think i understand completely where you are coming from in your point of view about your trade teachings and striking a nerve with you personally, i can detect that you went out of your way to make this latest presentation therefore it appeared to me to be a very important subject matter to you yourself, actually thought the presentation content was brilliant. My training as electronics engineer started oh about 40 years ago as a TV engineer and have since that time also had a natural interest in cars where electronics knowledge has been invaluable although i do realise that diagnosis in your field is different so the process of finding a fault has to be suitable to the environment. Really enjoy your presentations, you have a great way of getting your information across and think you have some wonderful knowledge. I remain a big fan. Tony
Thanks man. I promise to not bash the engineers so much in the future. There is a broken system from the top down that doesn't necessarily lay blame on the guy writing the flow chart.
Thanks SD, really appreciate your feedback and look forward to you showing us a better way to get the right diagnosis done maybe one day even on a Mazda 2 which i drive and have an odd problem with. Tony
Good on you Paul, this is what I learned in school. Volt meter and incandescent test light are your friend
great point SD PROVING OUT THE CICURIT WITH CURRENT FLOWING all the best
Great video! I never had to follow what a manufacturer was telling me because I've learned the correct testing procedure from Paul Danner and other great diagnostic CZcams channels! 👍
Sir Paul thanks for your kind teachings may GOD BLESS YOU AND YOUR FAMILY AMEN
Another excellent video...Thanks!!! It's like one of those movies you need to watch multiple times...
Working with circuit boards, so often I see where the power looks just like that jittery wave of your ground in the video (almost always a cold solder joint)...I'd say 75% of most circuit board failure issues are power-related (and often mechanical in nature)...
Forget about it...considering the load of a measuring device?....Make everyone cry. Thanks again.
I got "burned" a little using the DVM a few months ago fixing my horn circuit problem on the 1999 Silverado; the test light came to the rescue and proved I was chasing a ghost..
Great info dude! You’re right about flow charts using an ohm meter for testing, but when I go to Honda training (I’m an Acura dealer tech), they really push voltage drop testing now. So factory training is doing the right thing at least.
I view flow charts as more of a guide 😆
Exactly, a good guide too I may ad. Just not the tests they have you do to find the fault.
You’re a badass man!! I hear a lot of people saying you’ve changed their life in diagnostics. I wanna better myself in diagnostics. So guess whos joining your class? 🙋♂️🙋♂️
awesome! I look forward to hearing from you more, thank you so much
Dan Sullivan the guy who invented the load pro test leads, would always say in his videos that the problem is usually something simple. Case in point you found a corroded grounding spot on the engine block. The diagnosis may take some time, but the solution is something so simple.
You mean the guy that burned every bridge in this industry? He was his own worst enemy. It is a shame because he was a smart guy.
@@ScannerDanner LOL yeah him...he did seem a little bitter.
I've seen voltage drops in battery cranking and charging grounds. One shop couldn't understand why they were changing batteries (2) in a large truck. Battery ground was at a steel plate less than 1 foot from the battery. The steel was part of a steel body bolted to the truck frame, and there was a large flex ground jumper from the frame to the engine. One new triple ought (000) cable from the battery Negative to the engine block and a 2.6 Volt voltage drop went to .7 drop during cranking. No more battery, cranking and charging problems!
The health of a circuit can only be determined when it's capable of flowing the designed current at the designed voltage.
Makes total sense really. No one builds a circuit for the end-result of a resistance specification. The whole purpose of a circuit is to carry a specified current at a specified voltage.
I was testing a GM air conditioner system on an S10. I had power everywhere it was supposed to be, had ground too. Circuit still failed to operate when i plugged everything back in. I switched to a test light and checked my meter, power, when i touched test light it dropped to "0". All became clear, LOAD THE CIRCUIT!! It was a bad relay, burned contacts the post mortem revealed. So i am absolutely on board. I have also discovered that electrical engineers generally go by the mantra "looks good on paper", as we know, in reality outside the draft board, its all very different.
A valuable lesson, one you'll never forget
Can't wait for your next live! Loved to see NLA in the comments and getting ready for a camera man!
Many good points here and I'll make a point too. Comparing a low cost/accuracy multimeter to a high cost/accuracy scanner/oscilloscope isn't fair. And I'm with you on volt drop testing too.
it wasn't about a low cost meter. You could have used a fluke ohmmeter and it would have given you the same results. It was about the ohm test being a b.s. test in most automotive applications, yet that is what the manufacturer flow charts are full of. Ohm tests...or I should say b.s. 😂😂
Good job good teacher l always enjoy to listen and learn from you and thanks
SD is the GOAT
Lol I suppose that's good. :-)
Learned this long ago. A test light doesn’t lie! If I followed every flow chart I would have replaced a ton of modules that weren’t bad.
I've seen the original video many times. Very good information related to testing grounds.
Agree
Good video danner. I got burned on a lin bus recently... ya low current circuit that the ohm meter said was okay. Gotta load the circuit...
Awesome example of what you could be missing, this is the kind of stuff with an ohm meter that would cause head scratching and possibly replacement of an part that was good.
Car had two computers put in it before it got to me
Great informative video, good to see you revisited the important test procedure.
Current handling wire and connections with dissimilar metals & corrosion will get you over time; happens all the time with aging "stuff"; more so in the "salt belt" areas of the country.
Since this is the latest video, I hope Mr. Danner gets to see this question which is perhaps more of an opinion. Furthermore, I hope he forgives the long post.
My second profession before I retired had been working as an electrical contractor. Mainly in residential and office building market.
The electrical system in a residential unit consists of three wires that come to the top of the house electrical panel and a GROUND wire that usually comes out of the bottom of the panel. This heavy wire connects to the house cold water pipes that are buried in the street (ground) and usually an eight (8) foot solid copper rod that is driven into ground. Called ground rod. Basically, the purpose of the ground system is to protect an occupant should a live wire touches the body of an appliance. The ground wire in an outlet or appliance, routes the live voltage to “ground” rather than the body of an occupant. Thus, preventing a heart attack.
Now the reason for this post---I know I am probably going against many years of automotive electrical charts and training books, so bear with me. Why a body of an automobile is called “ground”?
There is no connection between the vehicles body and the earth. Rubber tires prevent an electrical connection. In a simplified DC circuit; in order for any circuit to work, it requires a path for 12V positive to reach the load. It also needs a path of return to 12V negative, which are the two terminals on the battery.
The automotive engineers figured that since there is metal in the frame and body of the powertrain, it would save wire (money) to use the frame as the path for negative voltage to battery.
That is a great idea, but why call it “ground”? Why not call it chassis? After all the negative wire of the battery is connected to the chassis of an automobile.
Anything, but “ground” makes more sense in a DC system.
I use an ohm meter quite often for things such as verifying I have the wire I want or that a bulb is good but for checking the integrity of a circuit I’ve used voltage drop tests for years in both automotive and aviation. An ohm meter just doesn’t produce enough current to identify a less then perfect ground or wire integrity.
I use voltage drop testing a lot of the time to pin point or get a general idea of where the break in the wire is or where the corrosion is. I really like to load test, I built a small load bank that can draw about 11 amps at 12.6VDC, you can draw in .5 amp increments on 4 switches and 1 amp increments on 4 more switches. It displays voltage on the circuit and the amount of current you are drawing. I see ohm meters get guys in trouble all the time. Manufacture troubleshooting sucks most of the time. It will lead you down a rabbit hole if you are not careful, and you will not recover your labor from them instructing you to basically misdiagnose it. I have spoke to a couple of the manufactures that my shop deals with and they more or less scoff at me when I bring up the use of oscilloscopes or dynamic circuit testing. "You can't do that you are going to damage our product!" Maybe, if you don't know what you are doing. I have never cooked a board, but I have diagnosed and repaired a lot of things that troubleshooting trees have missed. Love your videos man, you putting out good information makes us all better techs.
It can be the manufacturer give me advise but you still number one teacher in my book of automotive Scanner Danner aka Paul the man
Thanks malcolm!
Another great video ohm meters and resistant testing has its place and you are right high current wires need voltage drop testing will I don’t use your test lite method I do amp testing of the Circuit and yes only with the modules disconnected and after studying the diagram I check to see if the circuit can handle at least 10amps today’s vehicles uses more modules to control everything and electrical engineers really do not deal with corrosion , chafed wires and bad repairs to the wiring like we do
Ps I have seen a signal like the one in these video but it was not a bad ground it was a bad alternator diodes pushing a/c in to the electrical system it’s funny what havoc a/c voltage plays on this systems lol
Would like to know your take on the Sullivan Load Pro leads for meters...
Mr. Sullivan likes to publically bash people, including me, so I won't comment
ScannerDanner
I can appreciate that and definitely take that onboard, thank you...
Load Pro works, but it is not the "end all" tool. I have had cases with resistance the load pro didn't detect. Happened to me recently on a BMW with a loose ground cable.
Lynx Star Automotive
Good to know...
I bought a load pro few years back,convenient because it has a button but made poorly,cheaply that is. I would never buy another.
Great video Scanner Danner. Voltage drops test is the only way to go.thanks for all your amazing videos your a very sharp tech an trainer. I call my test light a scope on a rope.
Paul I attribute this to the fact that many do not understand the fundamental relationships contained within the confines Ohms' Law.
And if we do not understand the solid ground of those relationships then our understanding of Kirchhoff's' Laws are built on sinking sand.
if it's a bundled ground and the car isn't running the load may not be right and voltage drop could be wrong. always make sure the circuit is loaded properly or heavily!
yeah, repeating what you said more or less, people always forget that ;)
0:51 not to make fun of the engineer or all engineers in general, i(FNG as a dealer tech) had a 15 sienna come in for a no-a/c complaint, found out it has a code for the clutch lock-up circuit(essentially something that sends the signal to the computer to request a/c operation) well this vehicle had a new clutch-coil put on at the previous toyota dealer(out of state, why they put a clutch-coil on i dont know but thats what they did) but its still not working, fixed the pin fitment issue that it had in the circuit but it still didnt work, so now i(the FNG) took out my ohm meter and said well the coil has 200ohms(it was right in the middle of spec) of resistance so it must be good, take a closer look and you will notice the wires were not routed correctly so now did i just measure the resistance of my pulley? new clutch coil and it works now, ENGINEERS! WE LIVE IN THE REAL WORLD! resistence measurement is not always the way to go, i personally try to use a test light(kinda like what SMA made in a video) but ill use the peanut bulb for circuit integrity to check my wires, im sure i will get a lot of hate for this comment
edit: curious how bright/dim the test light would have been in that computer ground before the fix, thanks again for the great content!!
Paul, great video!!!!!!!!!!!!! Flow charts are like chasing ghost's down rabbit hole's!!!!!
Yeah, that is a good video . I watched it a long time ago . Voltage drop is the best way to test circuits
Better in this format I think. Other than the shameless plug at the end of my channel
I just had a great idea coming from the HVAC business 90% of technicians do not know how to use a multi meter or ampclamp Why don’t you try doing some videos on HVAC equipment troubleshooting I bet you get one hell of a response good luck
I have some HVAC stuff on cars, are you talking about residential?
ScannerDanner Yes testing residential HVAC components using a multi meter and amp clamp also troubleshooting you could have a whole Nother career path believe me
Excellent!
Yes you did it with your experience 🤍
Electrical engineer just got burned...good content Paul
You that man, love your info and leadership. Ohms test are only helpful for can network readings or looking for opens or shorts
What do you do on a car that randomly stalls? Dealer had had it for 2 weeks, no stall. I will take it home and 2 or 3 days later it will stall. Usually happens on a very hot day with a/c on. Never has a fault code.
Good luck, seriously, they can be that diffucult
@@ScannerDanner Interesting, so if I sent it up to you, you would need good luck to find the issue?
I would turn the job down lol. But seriously, you would need test equipment hooked up and make it your everyday car with a list of checks to do for each stall and wait 3 days for the next one? See what I mean? No thanks. Need to break it more first then bring it to me. I can't drive customers cars around like that.
@@ScannerDanner in other words, sell the damn thing (i would tell the prospective new owner it has that issue). Thanks. I really do understand. Sad thing, it is a 2005 trailblazer with 50k miles and looks and drives (when it does) like a new car. Oh well, sometimes a low mileage car is worse than a high mileage one. Love your channel.
Start doing some common failure searches, this can narrow down the area of where to start testing, then get it to do it more often. Do the tests yourself and use my forum. It's free to join.
Start with a throttle body cleaning and relearn then go from there.
I'm also an engineer and I say use an ohm meter Danner cause does what my tech manual says!!!ohh and I confirmed that with my poodle and she suggested the same thing.