How to Test an Alternator

Hi my car didn’t start so we called our battery guy and he replaced it for a time being with a temporary battery but after we stopped the car using this other battery the car wouldn’t start again so we jump started it and went home got our battery fully charged but then 1 week later car wouldn’t start again some guys said
It was a belt problem and the other guys said it was an alternator problem.
I think it’s an alternator issue anyway can I do this test if the car doesn’t start or is it for sir an alternator test.

It would really help to know please 🙏

Hi if I test negative of the battery to the engine block it gives a 0.00 reading. Is that a problem??

Chris, thank you much. I have a 1998 Chrysler minivan. I want to add additional white reverse lights so I can see better what's going on when I park. The question is, how can I check if the alternator can handle this additional load? In other words, how do I know whether I have a reserve of electrical power or not?

Jeez Louise, what a good presentation. Well-thought out, and helped me learn a lot. Not a "let's replace everything until it works approach", but an honest-to-God careful series of diagnostics. Had a suddenly dead battery in my Subie (no indications of dead or dying, just wouldn't crank one morning). Replaced battery but concerned about "Is it the alternator?". Now I know how to determine that. Thanks, pard!!

My dads truck has a poor start and I don’t know if it’s a alternator or battery thanks for the video

Thank you so much for the info you provided in this video! It is very helpful!

Thanks so much for ur video really appreciated man teaching us younger generations

What if you have a bad ground?

my car only goes up to 13.6 while onwith a brand new battery should i be worried?

Thanks Chris from a rusty old guy.

Wow this video is 9 years old and still VERY relevant! Thank you for showing how to do this!

Awesome. Thanks for test info

My alternator has good readings, but makes a whistling noise. I thought it might be the ps pump, but after unplugging the alternator while the car was running, the noise stopped.

My alternator is charging at 13.7 volts is that okay?

Love your videos Chrisfix! I used this video to diagnose an alternator issue with my 2008 Civic. It's almost at 300000 kms and your detailed and thorough videos are a big part of helping it make it to that milestone!

Good job Chris, Thanks

Ok, but how to you check the alternator itself, like the actual alternator? Not checking it through the car battery.

My volts shoots from 15.2 to 16.1 without accessories on is this normal? Or overcharging when I put on some load blower and lights it’s between 15.3- 15.7 volts

My in laws have a 2015 Kia optima charged the battery said it was good started up the car and it died in like 5 sec so I think the alternator is bad bcuz the past days they had to keep jumping there car but now it only stays on like a second but I fixed they had a draw with a bad brake pedal sensor but I fixed it now they have this problem car shuts offf after a sec so I thinks a bad alternator

Hi, when I connect the plus to the battery and then the minus to the alternator case (can not see the nuts) it shows around 14v, the multimeter is on Dc V, I dont have numbers. What does it mean?

-.01 to -.03 is what I got and I’m sure it means something is wrong with my connection some where but I’ve tried to clean it all up.

My Alternator Not charging. How to check and find faults

Your ground wire connection on the battery is loose.

how to check it before installing Altonatore???????????????????????????????????????????????????????????????????????????????????????????????????

What's that mean. Bad charging system.

Granpa showed me the old way turn ON car take off red terminal if car turns off. Boom! Alternator sucks!

WITH A FRESH BATTERY MY CAR IS STILL COMPLETETLY DEAD. NO LIGHTS AT ALL.

Thankyou so much straight to the point video

Chris you are very skilled. Your ability to teach even a person with no real experience. Thanks bud.

Thanks Chris. This was a refresher for me as it is many years since i had an alternator failure. Great video.

Honestly the video has incredibly happened me. 👊 Keep up the good spirit

What an excellent video!!!! Mind blowing how concise yet through all it is, thank you❤❤❤❤❤❤

I replaced the battery and with a load on the voltage is 13.67 with car on no load its at 13.56 volts. Should I concerned that the alternator is bad since im not at 14.2 volts.

The best explanation I've seen so far about to check an alternator. Thanks!

What if my battery light comes on and off every 1 minute

Alternator 13.6v is good with ac on, radio on?

So i have a 5-6v voltage drop when testing between postive terminal and the alternator post (and all other parts of that including wire, nut etc). What do i need to clean/fix if its the post that has the voltage drop? - post/bolt looks very clean it all looks new

Looking for opinions on how to diagnose my alternator, I get a big list of videos. I see one by ChrisFix and go, "Ah! ChrisFix did one. It must be good..." And I was right. You rock sir. Great vid and great info! Thanks!

Chris, excellent, excellent, excellent job, nothing else to say, comments proves it already, keep doing and keep sharing your knowledge.

So my key don’t work and I changed the battery but now the car is dead, this has to be an alternator ?

What a great video,kudos to you,straight forward right to the point

I do have a question. when i have my jeep turned off it's at 12.6 but when i turn it on it jumps up to 13.7.
however, when i turn on my AC and lights it stays at 13.7
I have a brand new battery and brand new alternator for my Jeep wrangler.
do you think i should be worried on the voltage that it's not at 14?

Thank you for this video. I was able to test out my alternator and make sure that it's charging the battery.

On the last test touching the b post you didn't say what the fix or problem is if it is above 2.8 . Mine is running ing at 0.6 .this stays at 0.6 touching each different point on the mentioned post of alternator

How did he raise the rpms from the engine bay? Can someone please explain?

Hi Chris,
Your videos are very helpful. Thorough, to the point, and easy to understand. No needless filler non-sense. Well done.
I'm going to go out and do the tests for my vehicle batteries and alternators and see what comes of it. Thank you! 🤘

Chris, this is an old vid but very useful. thanks I have a new battery and alternator I installed.
my voltage set point on the alternator is 13.9 while running. it sits at 13.45. I tested the negative/positive on the alternator case, bracket, engine block and reads .01 while accelerated. tested the positive to the bpoint and it reads .20 accelerated. I've sanded the bpoint connector and the battery wires, but I don't get it to read 13.9v, anything else I should look for. I couldn't find my ground wire to the chasis. if I disconnect the positive cable the car continues to run. thanks for your help.

So should I be driving with my headlights on all the time?

Thanks for sticking to the job and explaining it clearly. Thanks for not rambling on about Chinese parts, the War in Iraq etc etc. Good job, you now have yet another subscriber. (Pity I have to buy a new alternator tho)