VintagMustang302

I have a werid issue with my Mustang. If have a the lights or radio on in the car in and not running for like 2 min and the battery dies. :bang: I have replaced the battey and the alternator is like a year old.

It startes every morning fine. Just for instance if I go to put gas in it and if I happen to leave the parking lights on the car is dead by the time I'm done.
Is this a wiring harnes issue or does my car have a bum alternator?

jc69Stang

Are you sure the voltage regulator is wired right? Sounds like you have a short to ground somewhere.

If you have a meter, you can start your car and put one lead on the RED post on the back of the alternator and the other lead to ground. It should read over 12 volts. And the voltage should increase as you increase throttle to about 13.5 volts max. If you have voltage there, then move on to the regulator or wiring. Make sure everything is grounded right as well. A bad ground will ruin everything.
Good luck

VintagMustang302

I'll try that Thanks!

Paul

I agree. I'd get some fine grade sandpaper and start making sure all of the grounds were clean metal to clean metal. That's what finally cured one of my mysterious electrical problems.

Electricity is the damnedest stuff.