How to Test Vehicle Alternator with Multimeter! 

Perfect. This is exactly what I was looking for. And straight to the point too! Thanks.

Finally a straight to the point video thanks

I'm learning tonnes from your channel. Cheers from the U.K.

Short and to the point. Sweet! Thanks!

Thanks for the help, will be testing my alternator shortly.

Thank you for this quick straight to the point video! 👍👍

Thanks mate! I can now pin point whether it's the alternator or a break in the wires along the way to the battery. I was never taught that you can check this way only at the battery site. Awesome vid! Very helpful. These days it's too expensive to take to mechanics, they said it was my battery and I bought a new Bosch from them for $300 dollars plus their charge to look at it $185. Didn't fix the problem so I'm not going back for more problems. Thanks again. I'll continue to educate myself and figure it out. It's too expensive to have these problems these days even though I'm a worker.

Just what I was looking for. Thank you, sir.

Thanks brother! Excellent video! I need to do this test quickly because a storm is coming and my tractor is in the field and won’t start. I just put in a new battery and it started just fine throughout the day. Thanks for the quick and to the point video!!!

Thank you for a simple short and to the point video 💯🙏

This was so helpful, thank you for posting 🤜🤛

Thank you! Great video...simple and to the point 👍

Another easy method: first check voltage of battery with engine off then recheck the battery with engine on , if the voltage increases that means the alternator is working and charging. So your method tells you there is power to the alternator but doesn't tell you that the actual alternator is working. By doing the method mentioned above, you will hit two birds with one stone. Thank you

If my car doesn't start then how could I test alternator?

Thanks man, good video.

Thank u I've always had a hard time understanding how to use one for testing

Thank you! Straight to the point.

Thank you for sharing, very helpful. 👍

Good video thanks!!

Very good job explaining. How do I check the connection from the alternator and battery?

Thank you sir! Much appreciated

This was a GREAT help!!!

Great Job 😉👍🏽

Very good teaching thanks

This is what I was looking for. The engine noise was a bit much but otherwise a good video indeed. Thanks...

When checking the alternator output voltage make sure everything is off especially the automatic switch on the vw cc ! If anything is on the alternator voltage will be less than 14 volts .Cheers Eddie

Thank you bro! No BS!

Thanks dude.

Thank you 🍻👍

Thanks🤙

Question How do you go about diagnosing a car that had a battery replaced but comes back weeks later due to the car not being able to start unless if it’s jump started - Brand new battery was put on so maybe it’s a bad battery or a parasitic draw or a bad alternator or a bad or loose cable if I use a multimeter to test the battery while the car is on and it reads 12.4v that would most likely mean that the alternator isn’t charging the battery because if it was it would be over 14v+ with the battery reading 12v with the car on it would be safe to assume that it’s probably a bad alternator but what if it isn’t and I install an alternator and it still reads 12v how do I go about diagnosing it do I put the test leads on the alternator and ground cable to see if it reads 14v and if it does it means it’s good but if it doesn’t it means it’s bad like in this video how do I go about testing cables I guess I’m just wondering how you would go about diagnosing a car that comes in with a new battery that was replaced but dies weeks later and doesn’t turn on unless if jumped and the battery reads 12 v with the car running with a multimeter what do you test next ? I’m learning how to work on cars and I really want to learn how to diagnose

thanks a lot appreciate it

I wanted to do this test on my car, but the alternator is too low down in the engine bay, can't reach down there with other parts in the way.

What voltage should the alternator go down to , to know its bad

With the vehicle running I checked at the battery terminals with a voltmeter, and got 13.95 , do you think I might need a alternator

How do u check the alternator if the car doesn start?

Great video - what I needed. But I was so nervous the leads of the multimeter were going to fall into the belt when you started the car like that.

I find that my alternator has the same voltage as the battery (about 12.6), would that mean that I can disregard bad connectors and such as a problem and that the problem simply must be that I have to replace the alternator? Or can there still be other possible reasons for it?

How can i test the alternator when my car wont start?

How many Amps is alternator putting out?????? volts dont tell the whole story

There's another video that says the test should be done backwards. In other words the black on the alternator cable and the red on the casing, which one of you is correct?

would a bad alternator make your car surge at a stop signed ?

I needed to see if this is how you do it. I am not sure whether alternator went bad or a connection is bad. Battery is good but alternator doesn't charge. It's a brand new alternator.

What if your car won’t start?

Just what I was looking for!

👍

Does the car have to be turned on to test the alternator like that?

what car is that ? i love the location of that alternator ! so easy to remove. On my car , had to remove both rad fans , front right tire , splash shield and dipstick to remove it. A real PITA !

Couldn't you make the same measurement, with the engine running, but instead of AT the alternator, take the measurement at the battery terminals? That way you could rule out that there is something wrong/faulty in the wiring, or at the alternator for that matter and know the voltage that is truly making it to the battery. And if after running the engine for a while, say 30', and check the battery again, and if it is low or lower than 12 V then you'd know it was the battery is bad. Replacing the battery is less work and cheaper too.

Can't you just check it on the battery terminals?

does the vehicle have to be on to check? Can you do the test with the vehicle off and if it reads anything then it’s a defect?

Do not need that if you disconnect the battery while the car is running and it stop alternator is no good

if i get less than 14, like 12.50 does that mean I have a bad alternator?

My car doesnt start how can I test

Im not the smartest, but if an alternator isnt working properly, the car wouldnt be running? So whats the point of checking it? Or if the voltage on the battery is 14.7v while car is running, it would show the alternator is ok?

Thanks for this video. Pro tip, don't leave your multimeter resting above the fan belt/water pump and belts when you start your vehicle! Depending on the size of your engine and how much it rattles or roars when you start it, It could topple down and become mincemeat. Effectively destroying your fan, shroud, belt system, and maybe even bend or break some other things along the way. You also don't want too much wire hanging down when you start the vehicle. I would just follow all these steps, just don't introduce the multi meter until you're ready to use it.