How to Test an Alternator - Diagnose Charging Issues
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- čas přidán 7. 07. 2024
- In this video I show how you can perform an in depth testing procedure to determine the health of your alternator and charging system using a basic multimeter.
Multimeter Used in Video: amzn.to/2bngr5q
If you are having starting issues or are concerned about a parasitic draw (if you cars battery is drained when sitting overnight) please watch the following videos on how to diagnose a possible bad battery and also how to find a parasitic draw.
How to Test a Car Battery: • How to Test a Car Batt...
How to Find a Parasitic Draw: • How to Perform a Paras...
How to Replace an Alternator: • How to Replace an Alte...
Please Consider Supporting My Channel at : / rnwdue to factors beyond the control of Ratchetsand Wrenches, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. Ratchetsand Wrenches assumes no liability for any property or personal damage that may arise from doing a repair on your vehicle after watching any of my repair video's. Due to factors beyond the control of Ratchetsand Wrenches, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Again Any injury, damage or loss that may result from improper use of tools, equipment, or the information contained in this video is the sole responsibility of the user and not Ratchetsand Wrenches. - Auta a dopravní prostředky
Saved me a lot of time searching forums and reading opinions... thank you!!
A thousand thank yous! You just saved me north of $500 with your corroded terminals and leads tip. Kudos to you my new friend.
Oh my, I am so grateful for you. Thank you so very much, the guy at Auto Zone told me that my batteries were only paperweights at this point. He told me that because they were reading over 14 volts that they were overcharging and would blow up. I have two deep cycle batteries as well as my car battery, all of which he said are bad. I just bought the 2 deep cycle batteries from Auto Zone 12 1/2 months ago. Soooooooooooo Grateful to the LORD that I found you video, thank you. I think it is time for me to invest in a meter of my own. Thanks again!!!
11 dollars on Amazon or Walmart. Pays for itself in one use
I'm trying to diagnose an issue with my car, so far I've watched numerous videos, but so happy I found yours, because it's so similar. Not what what year that is, but I have a 2000 GT, very similar. Anyway, I just bought it, and it has sat an awful lot over about the last 8-12 months, barely ever being started, on a dealer lot. So I've had it two days, within the first few minutes driving off the lot, the battery light on the dash came on, once I got out of traffic and up to speed on the highway, it went off and stayed off. That was yesterday, today, it did exactly the same thing, except it would come on, then go off, a few times, but just the first few minutes driving. Battery and alt both tested good but the battery I was told did show weak signs, also my terminals are in absolutely awful condition; they're custom, large, look like copper, but the wires look extremely brittle and lots of corrosion where they crimp onto the battery. Drove into work tonight with no issues, light didn't come on, prob cause I drove a lot, seems like the more I drive the better it is. I'm pretty convinced it's either the terminals, and/or the battery. Gonna clean the terminals and drive it a lot tomorrow, then the next day I pick up a new battery. Anyway sorry for a wall of text, was curious if anyone had an opinion. I feel like since the battery is over 3 years old, closer to 4 years, with awful connections, plus sitting so much, it's one of these two or both, and not the alternator. Thanks for an awesome video!
HypnoticSuggestion 1
If you car keep burning lights, switches, sensors or any other electronics components and when you do the volts test 15 volts are present, 95% of chance your voltage regulator is bad, exellent video
great video and clearly explained. this has just helped me fix a battery drain issue ive had for the past 6 months. tracked it down to a connector on the battery neg near post with the voltage drop test. many thanks
One of the best explain videos of diagnosing battery and alternator problems.
Good video I knew everything you was talking about but it sure is nice to have somebody else still explain it to you again thank you
good video, clear instruction. Thank you
TOTALLY AGREE WITH YOU!
Great video. Would love to see a video on testing a wire sensor that connects to something important or even how to test fuses using a multimeter.
Thanks! this really saved me a trip to the auto shop. Awesome vid!
Thanks for this video! I was able to get the battery back to charging on my 78 Chevy K20!
Great video ! Learned a lot and will definitely be putting it to use. Thanks for spreading the knowledge
Keeslonkf np, glad you liked the video. Cheers
Excellent instructional video. You covered much more detail than others I've seen, but you kept it watchable. You win a Like, a Sub, and a giant stuffed animal with an eye that falls off in a week. Thank you!
You made the complex tech language easy. Awesome.
You nailed it, sir. Great video. Clear, concise. Thank you.
Thank you very much. I watch most of your videos and I really gain more knowledge .
Today my car was having electrical issues. I was pretty sure the issue with my car was the alternator. The car did not have any electrical power at all after I parked it. I jumped the car and it was ok then drove it for 10 minutes. I turned it off and the car has no electrical again when I tried to start it. Not even a dome light was turning on.After I watched your video my car worked fine. All I did was clean the battery terminals. My terminals looked clean and it did not appeared corroded. But after I cleaned them using sandpaper it worked better.
Thank you for your video. I just saved a couple of hundred of dollars.
Very informative, Thank You!
Well done video. Clear explanations and clear video.
Great video, I'm about to start troubleshooting a charging issue in my vehicle so I've been looking for some ideas and tips and this provided some good information.
Great video. I have a 1997 Jeep GC, battery was ok, would not start. I followed your instructions, and all tested fine. It turned out to be a defective battery. Thanks for your insight!!
+God Chaser Awesome, glad to hear a success story :) cheers
Best video - so clear - thank you :)
Best video for explaining alternator issues .
Reuben good job explaining it
so i just changed my battery in late october and in the cold illinois weather (-2 no wind chill) my car turned over super slow. the lights in the car dim considerably when the car idles between 900 and 700 rpm, or when im driving at night and i turn on the rear defogger and heat. any ideas? i dont want to jump to alternator conclusion and spend fat stacks on a new alternator if it isnt busted
Great video, thank you so much, very much needed help. Thank you so much again.
Good explanation. Thank you.
Great job. A video with an alternator that ISN'T producing output would be nice as well. You have 2 where the problem isnt the alternator. For example I had no output and shop quickly said they would change the alternator over the phone. I put in a brand new acdelco factor one and the car is producing 0 additional volts. So the actual alternator isn't the problem I need to solve.
Good video. Thanks for the help. thank you for sharing your talents
Premier Dance Center np, glad you liked it and thanks for commenting. cheers
Nice video personality I appreciate it for teaching us thank you very much
All very clear. Thank you.
Great and very helpful video; well done!!! Thanks!!!!!!!!!!!1
Many thanks for the great info
great video, thanks so much!
Hey man love the video. I have a question, I have the same car that is in this video and i am getting similar results from my meter----why do my daytime lights flicker for the first 10-30 seconds upon startup and then perform normally? Any help will be appreciated.
I'm only getting 12.4 volts with car running so I tested the voltage between the + battery terminal and + post on the alternator and it goes from 0.02 volts up to 8.0 volts and back down again in a constant cycle. What would cause this - bad diodes?
you are doing great job
Thanks and still useful in 2021, cos I have moved the battery to rear trunk, should I just measure the points between the rear battery and front alternator directly? and the reading still should not excess 0.2 v ? thank buddy much
hi good video,i had a loose cable on the battery on my jeep Cherokee and now the battery or alternator is bad I think,what do you think,thanks Lonnie
How about a video on finding vacuum leaks. Your videos have been a great help to me, thanks very much.
ok sure I'll see what I can do. Thanks for watching and your comment.
Thank you for your videos, very helpful.
Forgive me if this is a dumb question, I'm just curious. In the event one has an alternator with an internal regulator, could they add an external regulator between the alternator and the battery and that be a temporary solution until they are able to get a new alternator? I haven't tested my alternator yet because,as you suggested, I intend on watching your battery testing video because I feel my issue is with the it and not the alternator. I was just curious to weather an external regulator could temporarily fix a faulty internal regulator?
Regarding charging issues it is best practice to look at the simple things first. I learned this lessen at the ripe age of 14 tinkering around in my uncles auto repair shop.
Hi. Wonder if you can help. I have a 3 wire delco alternator. I have got 12.8v going into the cable on the bat terminal. When i put a positive lead from the multi meter on the V post it reads the same as the power going in to the bat terminal 12.8v As soon as the alternator starts to spin the voltage reading on the V post drops to 10.2V
How do I do voltage drop test if battery is in trunk? I came across another test where you put one probe on positive post of alternator then other lead on alternator case. What would this test show? Thanks and nice video!
great video. thank you.
Awesome video. Thanks!
Thanks a lot for sharing. This kind of material helps us save money and spares us from fake mechanics who only know how to change parts and charge one for it
Excellent video
Quick question (I am new on this) for Drop test from Alt terminal to Batt Terminal, did you change settings on the multimeter? or same 20V?
Sir what if the positive terminal of the alternator is burned i test my battery the alternator aint charging cause it does not beyond 12volts when the engine is running, how do u fix the burned positive terminal of the alternator?
Are the three wires on the back of the alternator,one for the 12 volts,one for “ground” and one for signal or computer controls?
Hi when I measure the voltage while the engineer is running, it is ~13.5Vdc. however out of curiosity I measure using AC via the multiplier and it's showing AC readings that's comes on and off around 8V. Does this means there could be some issue with the rectifier within the voltage regulator of the alternator?
So if the volts needle inside the cabin visibly increases (moves to the right) when my RPMs increase, that would be a sign of a bad voltage regulator right?
Nice video thank you!
VERY EDUCATIVE THANK YOU .REGARDS
With all accessories on my reading drops from 14v to 12.7. on another video I saw it's says that was fine . A little unsure ?
We are having an issue on a 2006 Honda Odyssey. The battery light is on. The vehicle is not stalling or anything but it acts like it is going to. The multi-meter shows 12.43 on the battery while van is off, once started dropped to 8 for a second then sits at 13.20 with A/C on then gradually starts to drop. Dropped under 11 before I turned the vehicle off. Any suggestions? I'd really like to get around buying an alternator if I can. Checked the connections, cleaned them just in case and they seem ok.
Thanks for the help ..
How spot on fundas r so clear Thanks Sir
I just replaced the alternator in my mom's camry. With the regulator connector connected it is slightly triggering the battery light, not bright but goes if i remove the connector. Is it normal for alternator to be hot to burn when touched? This was a remanufactured unit with the test report.
i have about .12 on the positive side, but the terminals look pretty clean. could i just connect a 2 gauge wire or something from the alternator to the battery and not have to worry about the factory wire?
Yours is the best explanation out of all the videos I have been watching, thanks
Thanks for sharing!
Great video. I installed a new battery, alternator and voltage regulator. battery reads 12.7 and with engine running it drops to 12.4. I did the voltage drop tests exactly as you have shown and they turned out to be within specs. Does this mean I bought a bad alternator off the shelf or can there be something else causing this?
+stupidgenious1 Have you checked voltage where it is immediately coming out of the alternator? and done drop down tests from there onto your battery? also when checking the voltage from the alternator make sure the washers and nut that are holding that cable in are in good condition and not dirty.
had an interesting problem - i own a 2001 Chevy Silverado 1500, 4.3L battery light started coming on and off - i checked voltage at battery while vehicle was running and had 12.4 volts. obviously battery isnt charging. thought alternator was failing so i removed the alternator and took it to Orileys and Advanced Auto to check it. both said it was 100% good. i re-installed the alternator. tested alternator by using multimeter from positive terminal on alternator to ground on engine block - 14.2 volts. so alternator WAS good. also now getting 14.2 volts at battery with engine running, so the battery is getting a charge now and no battery light. could it have been as simple as a loose connection somewhere??????
yes
Doug19752533 Did the problem return?
stupidgenious1 did you get it fixed?
how to test visteon alternator , ford mondeo tdci 130 hp
Is it possible that a rusty connection where the positive from the battery hooks to the alternator could cause my voltage to spike and fall at times?
my voltage well driving runs at 14.7-15.1 yesterday well pulling into a parking lot it dropped to 13.4 and tried to die then built back to 14.7 . battery was gotten five months ago car is a 2012 Chevrolet cruze .would this be alternator ,battery,voltage regulator,fuse box etc...
Very great video
thanks for educating us you are very clever wise person with humble personality how can we get direct instructions from you as I am living in U.K
good explanation
awesome video
any auto parts store like Orileys, Advanced Auto or Auto Zone will check it for free
i had a headlamp blown from a issue on my dash saying battery warning light flashing, also when i put load on it, it dims the headlights and dash lights, engine sort of lets off a breath you could say
I realize that this video is old, but I see that you are still doing videos. Thanks for the time and this video. My GF's 2010 Treverse's new battery is going dead after a few days. I found a .161 amp draw and have not been able to trace it down yet. However, while driving it, I noticed that the alt voltage, starts at 14.3 but within 45 sec it starts dropping to what the battery voltage shows when I start it, 12.4. I'm not much of a mechanic, but this seems like alt/voltage reg issues. Would you be so kind as to comment?
@Ratchets And Wrenches - 6:52 how do u do the test on the multimeter? do u measure voltage still on 20 volts setting? or am i testing resistance ? on the ohm setting? im confused
my headlights and internal lights flicker when engine is on in a 2001 v6 camaro? what could make this problem??
I have a 1990 Toyota engine 5A, my car has no signial when turn key on, I jump it, it start immediately, when turn off after running 20km, immediately it does not crank again. I check battery after 24hrs , it indicates 10.89V. should I change battery or alternator??? plz. thanks.
Plz tell me when you turn all the electrical system like a, light. Do we need engine 1500;2000 rpm at that time when all lights on. Or you can perform this test with normal rpm
excellent, thank you
What about if the alternator charge test is done with a battery that is not fully charged so it reads 11.9 volts before starting the car? This is my case and when engine is running and I perform charging test with everything electrical turned on and I'm getting 12.4
I have a 2006 ford focus. I bought new battery and alternator but still not charging. checked the fuses and they are good. any ideas?
nice work
Hello My Battery Light Come On On Christmas Eve, Turns Out The Alternator Was Bad I Replaced It And The Trucks Only Putting Out 10 Volts, I Also Got A New Battery, Any Idea On Why Its Only Putting Out 10 Volts On A New Alternator And Battery?
nice vid.. sry if i missed but while u were testing v draw resist between alt n batt what was meter set to ? ty
I would like to know the same thing.
I removed my alternator to replace my water pump and ever since my car has had a parasitic draw which causes a component to drain the battery from 12.4V down to about 8V when cranking in the morning.
Maybe did something to the voltage regulator or diode rectifier inside the alternator when I disconnected the alternator without first disconnecting the battery?
great video
Hey, great video. I'm mostly doing this check because my battery light is flickering in my car. My battery voltage seems to be within spec and the pulley directly connected to the alternator seems fine, but the one under it (like the one seen in this video under your alternator) seems like is making a whirring/clicking noise. Do you know how I go about repairing this or if I can even repair it? Thanks for the video, your channel is great.
nevermind, found your pulley video
what up my latino bro i need help. My car not charging the battery but i can start my car by jump starting then the battery juice up then die. both the battery and altenataor were tested good . then the guy told me it could be my fuse? at this moment i am cluless what shuld i do now please reply
i have 1993 pajero when i am driving suddenly blinking the dash board light indication and radio is off and on again what is the problem of my car? its is a battery or alternator, or probably loose connection.
thank you sir good job
Thanks a lot.
I hope u respond knowing this video is old but anyhow wen i connect the positive battery side and positive post on alternator on just idle i get .05-.07 i rev engine and it goes to .18-.25 so do i have a problem on positive side or no? Cause when checking voltage im getting 10.-9.vlts whether im checking just battery pos&neg or neg battery to pos on alt i kno its brand new battery that sat for long time in back seat never charged and after swapping out what i thought to be bad alternator and battery with junkyard alternator and this new battery i had but never installed those are my reading on my meter any thoughts oh and neg battery to alt housing at idle is .07 and stays .07 wen engine is revd please help
can I check alternator out of the car??
Hi I have Volvo 2008 XC70 my car sometimes when is sitting for about 1 hour it doesn’t start I jumped and started normal and I checked the battery is usually 12.9 and after I started the car Volvo the volts go up to 14.1 volts but after rep the engine doesn’t do anything stays the same volts
i changed the external voltage regulator and it's still charging way over what it's supposed to be what could it be?
Nice video thanks
Hey change alternator and battery still not charging what else can it be? It’s a town and country and with new part on battery terminals read 11 then 10.5 volts what could it be??
Very nice video
Did you happen to notice around the 3 minute Mark when you start the car it went below 9.84 volts? Isn't that a concern based on your testing the battery video?
Nice clear video. thanks for posting