Thread: Odd alternator problem...

I noticed my battery light was on, so I checked the voltage. It was running at 12.02 volts, and dropping when I gave it gas. Obviously the alternator wasn't charging. I started checking the voltage on the alternator itself to make sure it wasn't a wiring issue, and noticed it would jump when I touched the post that comes off the alternator, where the wire attaches. There's something wrong with that post somehow, and it's making it charge at times and not at others. Have any of you ever had this happen? Any idea how to fix it? There's an 8mm nut that looks like it holds that post on, but I took it off and the post won't come off.

The post shouldn't come off, as it's part of the internal charging system in the alternator. It sounds like something's bad inside the alternator. When you touch the stud and it charges, it makes me think the internal connection is bad. If you're feeling adventurous you could pull the alternator apart and try to fix it, but you're probably better off just getting another alternator.

One other thought: Make sure the charging cable that attaches to that stud isn't grounding out against the motor, exhaust, cradle, etc. That could cause a low charge condition, since some of the current will ground out through the engine. Also check to make sure the end of the cable isn't corroded to the point that it won't charge. Corrosion will greatly reduce the ability of the alternator to charge the battery.

I checked the wire first, because it's new. It's perfectly fine. The post does move a tad, but doesn't seem to come off. I have no problem taking the alternator off and messing with it, I had planned on doing it anyway. If I can't figure it out, there's a shop here that rebuilds them, I'm sure they can do something, they've rebuilt it before lol.

if the post moves then for sure that aint right

Anybody ever took one apart? The casing itself? I can't figure out how to get it apart lol.

Cancel that, I got it. I was being too gentle lol.

For those interested that post DOES come off lol.

ya takeing apart alternaters and starters was a part of auto tech in high school just be carefull its not hard but has some small parts it might be the conection brushes (dont remember part name sorry its been 7 years) they could be bad connection there or blown rectifier dout it though look up alternater rebuilds and do it your self save u $

Yeah I got it all apart, just have no way to test any of it lol. I broke one of the brushes messing with it.

see told u be carefull lol u might be able to get a brush kit for $10 or so if not go pull a part were the brushess warn? lossing contact? fix brushes and take to pepboys or advanced they test them i thank or is it bat and starter if not reinstall test and repeat sorry cant help more just bont know many was to test with out runing in car