Car has done this twice now.
89 gta

1st time... lights were on, it was dark. Realized lights were going dim, fast. Guage showed almost in orange, and the needle was visually moving. Turn fog lights off to save power, and getting ready to turn lights off to try and save power to hopefully make it into town at least... Magically, the lights light up instantly, and the voltmeter is back to normal. Hmmmm. Weird.

Week or so later...during the day on way to work, turn a blinker on. The blinker stays lit, on, for about 2 seconds, then goes off. Look at voltmeter guage. Uh oh . Pull car into parking lot. Turn car off. Not enough power n battery to crank it.

Later that night, I jump it off. Turn parking lights on. Start towards home. Bout an 8th mile sown the road...it magically starts to work fine again.

So...what is it? Voltage regulator in alternator?
Could it be something else? I noticed that the battery sparks when connecting and disconnecting the negative battery cable. Eliminated this by unplugging the headlight control module to the headlight motors. Drove it around a while. Hasn't happened again, yet. Headlight control module bad?

Appreciate any help. Be nice to trust driving my car more than a half mile from home.


Edit: While it was working, car running...voltage about 14.5-14.6.
Charged up battery yesterday. Battery was at 12.6 this morning.
Just drove it a while. Battery voltage is 12.6. I think battery is still good. And alternator charges fine...at least when its "possibly" working

edit2:Quit charging again, with headlight motors unplugged at module...so it's an intermittent noncharge from the alternator, I think. Unless someone gives me another idea, I'll just go get me an alternator, and recharge my battery before installing.

 

I would say a new alternator and you might possibly wind up having to buy a new battery also. I say this because when my alternator went out it spiked my battery. I could put a full charge on it and the lights worked and everything, but the car wouldn't start even though it showed a full charge with a multimeter. Checked the amperage and it had none.

 

I bought a new alternator.
Will see how that does.

Still curious if the headlight motors are supposed to be drawing current, though.