How to Test Vehicle Alternator with Multimeter!

[@powerfulsun7248]

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

[@Flashback502]

Thanks for helpful tips, may use this. You're welcome! Please subscribe like and share and check out our other helpfull videos

[@jermainejones6564]

Finally a straight to the point video thanks

[@Flashback502]

Your welcome glad could help please subscribe like and share and check our my other helpfull videos.

[@marty3076]

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.

[@Flashback502]

Your welcome , yes agree the more you learn the more time and money u save. Hope u fix problem.

[@obiwanrazzy]

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

[@raulescobar3881]

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!!!

[@Flashback502]

Your welcome hope all works out. Please subscribe like and share and check out our other helpfull videos

[@rawalbikash2225]

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

[@Velofire_21]

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

[@Flashback502]

You're very welcome glad could help please subscribe like and share and check out our other helpfull

[@JourneyMN]

Quick and strait to the point. Thank you.

[@Flashback502]

You're welcome! Glad could help Please subscribe like and share and check out our other helpfull videos

[@RJ6AV6]

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

[@Flashback502]

Your welcome

[@globally123]

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

[@Flashback502]

You're welcome! Glad could help Please subscribe like and share and check out our other helpfull videos

[@mobilehomelife4028]

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

[@rasgum7]

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

[@Flashback502]

You're welcome! Glad could help Please subscribe like and share and check out our other helpfull videos

[@humrod1852]

Short and to the point. Sweet! Thanks!

[@MLife1000]

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

[@Flashback502]

You're welcome! Glad could help Please subscribe like and share and check out our other helpfull videos

[@edwardedward7974]

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

[@Flashback502]

Thanks for tip. Please like subscribe and share

[@ButterfatFarms]

Just confirming the alternator is putting out DC voltage above that of the battery voltage is a very basic test for an alternator. You also need to check the AC Ripple voltage. Cut and paste FYI... ( I would suggest measuring AC Ripple directly at the alternator between the case and the positive terminal) How to Test for Alternator AC Ripple Testing for AC ripple is a straightforward process, you just need a multimeter with a low AC setting. Testing Procedure: 1) Set Up the Multimeter- Set your digital multimeter to the AC voltage setting. The scale should be set to a range that can detect low voltages, such as 0-2 volts. 2) Connect the Multimeter- Connect the multimeter’s positive lead to the positive terminal of the battery and the negative lead to the negative terminal of the battery. This setup allows you to measure the AC voltage present across the battery terminals. 3) Start the Engine- Start the vehicle and let it idle. Observe the multimeter reading. In a healthy system, you should see a very low AC voltage-ideally below 50 mV. 4) Rev the Engine- Slowly rev the engine to about 1,500 RPM. The AC voltage should remain relatively low and stable. If the AC ripple increases significantly with engine speed, this could indicate an alternator issue. 5) Evaluate the Results- If the AC voltage exceeds 100 mV or fluctuates wildly, it’s a sign that there may be a problem with the alternator, such as worn diodes or stator windings. In such a case, further inspection or alternator replacement may be necessary. What to do if your AC ripple is too high High or irregular AC ripple can be caused by one or more open diodes in the rectifier bridge or by a fault in the stator windings. Since it doesn’t really make sense these days to replace internal components, replace the alternator with a new unit.

[@Flashback502]

Thanks for helpful info.Please subscribe like and share and check out our other helpfull videos

[@yivonnevaldez9697]

Thank you! Straight to the point.

[@Flashback502]

Your very welcome please subscribe like and share

[@jefffoust1698]

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

[@Flashback502]

You're welcome! Please subscribe like and share and check out our other helpfull videos

[@richardlisiura3025]

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

[@Flashback502]

Glad it helped

[@GCSimons]

Appreciate the help, exactly what I needed. Well explained, thank you

[@Flashback502]

You're welcome! Glad could help Please subscribe like and share and check out our other helpfull videos

[@Human_Taxidermist]

Thank you so much!!! ❤

[@Flashback502]

You're welcome! Glad could help Please subscribe like and share and check out our other helpfull videos

[@christophermarsh4497]

This was so helpful, thank you for posting 🤜🤛

[@Flashback502]

You're welcome

[@SuperHOGGA]

Another site tells you to avoid puting the black lead onto the alternator casing itself , and to put it onto another independant metal part ( bolt , nut etc) . to avoid possible damage.

[@ANuisanceRockBand]

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.

[@Flashback502]

Lol yea using clips would help

[@thisguythatguy7472]

Very good teaching thanks

[@Flashback502]

You are welcome

[@lindarpel]

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

[@powertoyz]

Simple and easy! Good video

[@Flashback502]

You're welcome! Glad could help Please subscribe like and share and check out our other helpfull videos

[@solo3071]

Perfect. Quick and effective Thanks!!!!!!!!!!

[@Flashback502]

You're welcome! Glad could help Please subscribe like and share and check out our other helpfull videos

[@bermbuster6]

Thank you sir! Much appreciated

[@Flashback502]

Your welcome glad could help please subscribe like and share and check out our other helpfull videos.

[@fireboyisme]

Good video thanks!!

[@LeCigareVolant]

Thanks man, good video.

[@JohnnyGutierrez-um6nt]

This was helpful thank you ❤

[@Flashback502]

Glad it was helpful!

[@DGander007]

Some alternators only start charging once the RPMs are above idle. Such as my boat alternators. Just an FYI. my voltage will pretty much read what my batteries voltage until I rev up the RPMS above 800RPM. Then the alternator sends 14v to the batteries.

[@Flashback502]

Thanks for helpful Info. Please like subscribe and share

[@ronpolk1937]

Great video. Thanks!

[@Flashback502]

You're welcome! Glad could help Please subscribe like and share and check out our other helpfull videos

[@jimiboii209]

Thank you bro! No BS!

[@Flashback502]

You're welcome glad could help.

[@vernondavis2207]

This was a GREAT help!!!

[@Flashback502]

You're very welcome! Glad I could help. Please subscribe like and share and check out our other helpfull videos

[@Misfits89]

Homeboy pals with fire by putting those leads so closed to the moving alternator

[@baltazaresquiveliii3387]

Thank you for sharing, very helpful. 👍

[@Flashback502]

Your welcome glad could help please subscribe like and share and check out our other helpfull videos.

[@BigmoRivera]

Great Job 😉👍🏽

[@Flashback502]

Glad could help👍Please subscribe & like and share if haven't already and check out our other helpful videos

[@justjoe942]

Thanks dude.

[@Flashback502]

You're welcome! Glad could help Please subscribe like and share and check out our other helpfull videos

[@kensheffield343]

Thanks Bro

[@josegarrido7021]

thanks a lot appreciate it

[@Flashback502]

You're welcome! Glad could help Please subscribe like and share and check out our other helpfull videos

[@turbro7185]

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

[@Flashback502]

Most likely its your alternatetor. You can take it to Auto Zone and have them test it. Please like subscribe and share.

[@mymusic3354]

Just what I was looking for!

[@Flashback502]

You're welcome! Glad could help Please subscribe like and share and check out our other helpfull videos

[@StarClay666]

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?

[@Flashback502]

If your vehicle is not charging correctly, then it's most likely a bad alternatetor. Please like subscribe and share.

[@scooby196I]

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.

[@kenmyers1324]

Thank you 🍻👍

[@Flashback502]

Your welcome glad could help please subscribe like and share and check our my other helpfull videos.

[@djspbb]

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.

[@Flashback502]

Have a video up showing how to test alternatetor. please subscribe like and share and check out our other helpfull videos.

[@GregAliano]

Thanks🤙

[@Flashback502]

Your welcome glad could help please subscribe like and share and check our my other helpfull videos.

[@bcbjbggjh9102]

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

[@Flashback502]

Yes can cause this. please subscribe like and share and check out our other helpfull videos.

[@makingtoast5479]

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

[@Flashback502]

If your vehicle is not having any power problems, then it should be fine.

[@jamesbroomfield7799]

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

[@vandshome]

Hi is 13.59 good for an alternator in a 2010 4cl Camry?

[@Flashback502]

If your battery is charging up, then it should be good. Please subscribe like and share and check out our other helpfull videos

[@zamz7978]

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?

[@r4a2g0]

I did this and the alternator was reading between 13.55 and 13.70. does that mean its not working optimally? The car occasionally has trouble starting.

[@KjH-sq1sz]

Hi mate, when perform the same test, my alternator is only reading 12.3volts, it's a brand new alternator a day old, new battery fitted 2 days ago as well. Would you say my alternator is fckd ?

[@Flashback502]

Most likely it's good. The reading can be different on different alternators.

[@dasboot360]

I keep getting around 12.8. And I just changed the alternator yesterday. Do you think it’s a bad alternator?

[@alexalexftw]

You can just check on battery terminals its the same thing

[@Richard-eg4ms]

My alternator is showing 13.5 volts. Rev engine does not go above 14 volts. HELP

[@Dibran9mm]

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

[@gaiden9423]

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

[@AdrianReyes-hr3tg]

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

[@annagodina6666]

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

[@Flashback502]

Yes

[@quickerticker7901]

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

[@villamizar30]

👍

[@humrod1852]

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.

[@Flashback502]

Yes agree 👍🏿

[@dcole302]

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

[@sophiademelo21]

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 !

[@Flashback502]

Yea some are a. Real pain this is a chevy avalanche. please subscribe like and share and check our my other helpfull videos.

[@Kalanimauimusic]

What if your car won’t start?

[@user-cg7jp7jt4v]

My car doesnt start how can I test

[@Flashback502]

If it doesn't start you'll have to take it off and have it tested. You have a battery issue. Please like subscribe and share.

[@xGaLoSx]

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

[@Taun24]

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?

[@TheMalhazar]

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?

[@Soulvex]

Multmeter

[@Flashback502]

👍🏿 please like subscribe and share