Originally Posted by cabbottusmc1803
Anybody have any idea what that wire was and if my alternator is bad or if its something different? And any help with the capacitor problem if It is one would be nice also.
that is the output wire from the alternator and gets spliced into the hot side of the ignition system within the wiring harness, basically it gets hooked up to battery positive. Without looking up the wiring diagram in a service manual i can't tell you exactly where it goes or what wire it gets spliced into, but it usually gets spliced into a main feed running between battery positive and the starter. if that's not connected, or poorly connected, you will have **** poor output from the alternator... because the output wire isn't connected. It sounds like work had been done and the wire got busted or cut and they did a bad job to fix it. You should either have it soldered and shrink tubed to insulate it or use a good crimp and shrink tube that.
How do you figure the capacitor would help with headlight dimming?
It might... remotely might... prevent flicker or pulsation. and if you had pulsation that would be from the alternator's voltage regulator and/or rectifier going bad in which case needs to be replaced.
like was said, if the car has an underdrive pulley which is a smaller aftermarket crankshaft pulley that had been installed to get a little more horsepower by reducing parasitic loss by turning all the accessories (alternator, ac compressor, power steering pump) slower then the alternator is turning slower which results in not enough power output and if you have headlights, heater, and radio going at idle rpm the voltage will drop below 13v.
The other case is the alternator is on it's way out, provided it's wired properly and no other wire connections are bad. And unless you know how to replace the rectifier and/or voltage regulator in it then you just swap out the whole alternator for a new one at the parts store.