My alternator has gone out.

My car has been sitting for around a month and 2 weeks now. Yesterday, i went to start the car, and it did not start(dead battery). So i jumped it, and it started right up..

I also recently aquired 2 12's for free, and decided i would finally put them in. So i did. They sound nice.

So, after starting the car, i would rev it and hold it at 2000 for about a minute on and a minute off, just to help reveive the battery... while doing this i also had the system sorta bumpin. Not too loud thought because of the neighbors.

Thats when the battery light came on, and my volt meter began to drop RAPIDLY.

So now im stuck with a low batt, and a dead alternator -i would assume the alt. because the batt volts were dropping while the car was started.

What is the most common cause, or reason, for an alternator going out? It is basically a spinning rod, so how is it that it can go out? Do the brushes wear out, or short? whats the cause? Could the problem have also been initiated by having my sytem on?


Senior Member
hrm...what id do is go to pep boys- buy a prostart alternator and go put it in. if it fixes your problem and your system blows another alternator, return the alternator and get another one for free. this is basically what I have done with 4 alternators until I got a capacitor. Kinda sucks takin everything apart/ puttin back together. also check your grounds they could have corroded and grew some white powder- clean it off and try again.
yea my sytems grounds and everything are fine.. and i already plan on buying from autozone because of the lifetime warranty. I would just like to know the most common cause for alternator failure.


Senior Member
my friends dad used to rebuild starters and alternators till he died late last year, and he told me there are diodes inside of the alternators. He said that when you have a system it sucks alot of power through these, thus creating heat. the heat burns them and fries them till they are useless, then you get no power through them. you could replace the diodes- I think there are 3 of them, and you can get ones that allow more power to get through them with out so much heat.

not so much the systems ground, but more the battery ground


Senior Member
ya this is generally what happens.....alos old age of an alternator and hooking up a system can def cause them to shit out also consider having the one you have rebuilt if there is a place that does it locally. this way u know what your getting because if you buy a "new" one you just getting a rebuilt one anyway and they can shit out to. also most places that rebuild them will warrantee it and you will only spend halfthe money to have it done. Hope that hellps u out