I see a lot of older mechanics in the comment section saying that voltage drop testing is a newer thing they've attempted and that it works. Makes me glad I'm taking note of this as an aspiring tech. I feel like in the modern automotive world, you can't become a well-rounded tech without getting your electronics down.
Pretty cool alright. I also figured out why I was blowing subs and amps and head units in my car. After much studying and research I finally had a Eureka moment and now I get Voltage rise when I’m pounding my sound system in my car. Great tutorial by the way 😎👍
I've been a professional tech for 45 years. I hate to admit that the first twenty years did not include an understanding of the value of a voltage drop test. I felt like a genius when I diagnosed an issue where the previous tech had crimped insulation into the terminal. Multiple techs had tried to figure it out and I had just discovered the voltage drop test. It was an eye opener and led to a whole world of understanding. I'm glad you used a scope to explain this test because it really shows a great visual.
@@710diagnosticsandfishing It certainly is. I witness the lack of understanding with the majority of techs out there. Understanding it's value, especially for connections and switch contacts under load is invaluable.
Not a mechanic here, but have a decent basic understanding of electrics through my job in Telecoms. It took a moment or two for the penny to drop as to what you were actually reading, but when it did, it was a wow moment for testing vehicle electrics....Essentially you are looking for a HR or HR Shunt between the two points of the circuit by measuring voltage drop. Is there a reason you prefer to do it this way rather than just measuring the between the two points? I am guessing measuring resistance between the two points on the Positive cct won't pick up a HR short to ground/negative?
One of the major issues with automotive electrical testing is limited access. This is one of the many techniques to overcome this problem. The typical process when testing a live loaded circuit is to test across the two points at the component, traditionally. Which is good practice. The issue typically arises when a technician measures a lower voltage than expected. This is where this method comes into play. It's common for a technician to assume a low voltage measurement is an issue on the positive side of the circuit. Vdrop testing is a quick way to determine which side of the circuit the fault lies. Here is another video, essentially explaining that every measurement you take with a volt meter is a voltage drop test. czcams.com/video/tH0Hdwp7mcQ/video.htmlsi=3zcDYVWSt88BUj9C
I'm not exactly sure what you mean by the battery is a load. I like to think of the battery as the start and finish of the race/circuit. Every complete circuit, uses all of the potential/voltage of the battery to complete the race/circuit. This is regardless of the resistance of the circuit. But knowing this, we can test the voltage drop across a load and determine if all of the potential/voltage is used up on this one load or are there additional loads/resistance in the circuit. If we see 1v less across the load than what we tested at the battery, then we can, use voltage drop testing to determine which side of the circuit has the additional resistance. I hope this helps.
I have been a mechanic in the 80ies ,never used a lab scope ,the other day i was working on a 2010 mazda3 ,i did a test on the negative side of the battery to ground and found 5.8volts i was shocked ,
It is hard to be efficient in todays world without a scope. I still spend a lot of time with a meter and testlight, but when it's time to break out the scope, it's worth the investment every time.
I'm not exactly sure what the question is? Load pro is another way of achieving an accurate voltage drop test. I've heard a lot of good things about the Load Pro, but I've never used one.
@@710diagnosticsandfishing , thanks for your response. Sorry for assuming you had used/tried a set of Load-Pro test leads. Was wondering how they compared in your experience. I like them as you can quickly test both the positive and ground wires quickly. They will quickly identify a very small wire leak as well as tell you which wire is the culprit. Thx again for your video.
The only time the voltage difference is "12v" is when I have the light switch off, and momentarily, as I'm switching between the fuse, for the circuit, and the resistor that I used to simulate a high resistance point. I used a sealed beam headlamp as the resistor. I had that connected inline, instead of the fuse, then swapped it to the fuse to "fix" it. Anytime the load/vehicle headlight is not connected, there will be minimal vdrop, because, no current is flowing. This means the available voltage at the connector is similar to the available voltage at the B+ stud. This is the case as long as the circuit is unloaded. As soon as the circuit is loaded, any resistance from the B+stud to the positive at the headlight connector will cause the available voltage at the headlight connector to drop. This happens on every circuit that carries some current. It is up to us to determine if the measured amount of voltage drop is an issue or not.
Can carry amperage.. dude, its current, and that being said I dont watch trash channels calling the laws with their pet leek name.. whats next line, something about wattage?… stoppage please..
Lol, thanks for the feedback. I do interchange similar terms occasionally. 😅 Occasionally, I'll even make a mistake (error performed unintentionally) 🙃 I only pick the pepper out of fly sh!+ for money (monentary compensation). I don't really see the problem with using current and amperage interchangeably. I would be open to enlightenment on the subject. I'm learning just like everyone else. Dude, I wish I knew it all. But until then, I'll just have to listen to the criticism and feedback while continuing to try to improve. I'll try to be more accurate in my use of vocabulary. Thanks again. Have a great day I'm headed out to catch some aquatic marine life (fish).
@@710diagnosticsandfishing I have heard ( and probably used!) the terms "amperage" and "wattage" many many times over the years, and never knew they were incorrect! Plus everybody seems to understand those terms when they are used lol Your reply about fly shit and pepper is right on the money....
I see a lot of older mechanics in the comment section saying that voltage drop testing is a newer thing they've attempted and that it works. Makes me glad I'm taking note of this as an aspiring tech. I feel like in the modern automotive world, you can't become a well-rounded tech without getting your electronics down.
Pretty cool alright.
I also figured out why I was blowing subs and amps and head units in my car. After much studying and research I finally had a Eureka moment and now I get Voltage rise when I’m pounding my sound system in my car.
Great tutorial by the way 😎👍
I've been a professional tech for 45 years. I hate to admit that the first twenty years did not include an understanding of the value of a voltage drop test. I felt like a genius when I diagnosed an issue where the previous tech had crimped insulation into the terminal. Multiple techs had tried to figure it out and I had just discovered the voltage drop test. It was an eye opener and led to a whole world of understanding. I'm glad you used a scope to explain this test because it really shows a great visual.
It's never too late to learn. This is easily one of the most overlooked fundamentals.
Thank you for watching.
@@710diagnosticsandfishing It certainly is. I witness the lack of understanding with the majority of techs out there. Understanding it's value, especially for connections and switch contacts under load is invaluable.
Really appreciate this video Mike. Taking it back to the basics.
Nice job ! This is the skill to understand! Subscribed!
Awesome, thank you!
Great tutorial ! Clear explanations ! Thanks !!
Great explanation, Thanks!
fantastic well explained
Love it!
great video' can you please show us where you connected the test leads'' its not clear in my mind
The positive lead is at the fuse box positive stud, and the negative lead backprobed at the headlight positive
Not a mechanic here, but have a decent basic understanding of electrics through my job in Telecoms. It took a moment or two for the penny to drop as to what you were actually reading, but when it did, it was a wow moment for testing vehicle electrics....Essentially you are looking for a HR or HR Shunt between the two points of the circuit by measuring voltage drop. Is there a reason you prefer to do it this way rather than just measuring the
between the two points? I am guessing measuring resistance between the two points on the Positive cct won't pick up a HR short to ground/negative?
One of the major issues with automotive electrical testing is limited access. This is one of the many techniques to overcome this problem.
The typical process when testing a live loaded circuit is to test across the two points at the component, traditionally. Which is good practice. The issue typically arises when a technician measures a lower voltage than expected. This is where this method comes into play. It's common for a technician to assume a low voltage measurement is an issue on the positive side of the circuit. Vdrop testing is a quick way to determine which side of the circuit the fault lies.
Here is another video, essentially explaining that every measurement you take with a volt meter is a voltage drop test.
czcams.com/video/tH0Hdwp7mcQ/video.htmlsi=3zcDYVWSt88BUj9C
Good job but maybe using a little drawing board with showing where you put the resistor between to leads would also help
Thanks for the feedback. Good tip, I will try something like that next time.
👍
Great job! So basically the battery is a Load, so between both points +/- is 12.6 volts meaning resistance/ohms. I’m I getting this right? Thank you
I'm not exactly sure what you mean by the battery is a load. I like to think of the battery as the start and finish of the race/circuit.
Every complete circuit, uses all of the potential/voltage of the battery to complete the race/circuit. This is regardless of the resistance of the circuit. But knowing this, we can test the voltage drop across a load and determine if all of the potential/voltage is used up on this one load or are there additional loads/resistance in the circuit.
If we see 1v less across the load than what we tested at the battery, then we can, use voltage drop testing to determine which side of the circuit has the additional resistance.
I hope this helps.
Like the video
I have been a mechanic in the 80ies ,never used a lab scope ,the other day i was working on a 2010 mazda3 ,i did a test on the negative side of the battery to ground and found 5.8volts i was shocked ,
It is hard to be efficient in todays world without a scope.
I still spend a lot of time with a meter and testlight, but when it's time to break out the scope, it's worth the investment every time.
One question
Thatcher tools can be used to scan european cars
Thinks
I'm not familiar with that brand.
Load-Pro? Thx.
I'm not exactly sure what the question is?
Load pro is another way of achieving an accurate voltage drop test. I've heard a lot of good things about the Load Pro, but I've never used one.
@@710diagnosticsandfishing , thanks for your response. Sorry for assuming you had used/tried a set of Load-Pro test leads. Was wondering how they compared in your experience. I like them as you can quickly test both the positive and ground wires quickly. They will quickly identify a very small wire leak as well as tell you which wire is the culprit. Thx again for your video.
Why is the voltage difference 12v when the connector is disconnected from the light
If you tell me the exact time, in the video, that you have a question on, I'll explain it.
Because no load is being applied to the circuit.
The only time the voltage difference is "12v" is when I have the light switch off, and momentarily, as I'm switching between the fuse, for the circuit, and the resistor that I used to simulate a high resistance point.
I used a sealed beam headlamp as the resistor. I had that connected inline, instead of the fuse, then swapped it to the fuse to "fix" it.
Anytime the load/vehicle headlight is not connected, there will be minimal vdrop, because, no current is flowing.
This means the available voltage at the connector is similar to the available voltage at the B+ stud. This is the case as long as the circuit is unloaded. As soon as the circuit is loaded, any resistance from the B+stud to the positive at the headlight connector will cause the available voltage at the headlight connector to drop. This happens on every circuit that carries some current. It is up to us to determine if the measured amount of voltage drop is an issue or not.
Can carry amperage.. dude, its current, and that being said I dont watch trash channels calling the laws with their pet leek name.. whats next line, something about wattage?… stoppage please..
Lol, thanks for the feedback.
I do interchange similar terms occasionally. 😅
Occasionally, I'll even make a mistake (error performed unintentionally) 🙃
I only pick the pepper out of fly sh!+ for money (monentary compensation).
I don't really see the problem with using current and amperage interchangeably.
I would be open to enlightenment on the subject.
I'm learning just like everyone else. Dude, I wish I knew it all. But until then, I'll just have to listen to the criticism and feedback while continuing to try to improve.
I'll try to be more accurate in my use of vocabulary.
Thanks again. Have a great day
I'm headed out to catch some aquatic marine life (fish).
@@710diagnosticsandfishing I have heard ( and probably used!) the terms "amperage" and "wattage" many many times over the years, and never knew they were incorrect! Plus everybody seems to understand those terms when they are used lol Your reply about fly shit and pepper is right on the money....
👍