[raven1991]

I have restored a stock 89 coupe 5.0 and the alternator light stays on; also the gauge shows that there is little output. I have replaced the alternator with a new one, and an alternator that is known to work, yet the light is still on.

Any ideas on why the alternator is not working. Could it be something other than the alternator?

[Nyt_Muves]

Well, there is a slim possibility that you got another bad one... Right out of the box... Most of us have gotten a bad something or other before...

However, the easiest thing would be to take the alternator, once it is off the car, to an Autozone. They have a machine and can test the unit on the bench seperate from all other components, and can tell you for sure if your alternator is bad. The testing is free. Takes about a minute. At least you could eliminate it as a possibility or confirm that you have a bad one...

[raven1991]

Thanks but I even used the alternator off my 91 5.0; this is my daily driver and it works for sure. It can't be the alternator.

[lxarlo]

maybe one of the fuseable links in the charge circuit is open. check what the voltage is at the battery with a volt meter. it should read 14-14.7 volts is good. it looks like now is a good time to do a 3G alternator swap. i just finished doing that on my brothers car today. his alternator was charging weak for a while. i had replaced the regulator on the back of the alternator, after it was going haywire and extremely overcharging. it worked fine for a while, and now the stock one is dead again.