could be voltage regulator or sometimes the alternators from the store are bad best thing to do is have them test it before you leave the store or even purchase it you should look for a problem outside the alternator. if you replaced it with a decent rebuilt or new and are still having problems check the battery, battery cables and your ground cables. Make sure your battery is secure and nothing can short across the terminals. This can burn out the regulators. Check your belt tension as well if it is loose the alternator pully might not spin properly.
Typically, a bad or "going bad" alternator.
Alternator going out.
It could be your alternator is going bad
Generally, as you face the car from the front, the alternator should be on the left side of the engine where the belt is. The belt drives the alternator. The alt in my '96 is right up top. You'll see an electrical connector going to it.
The alternator may be going bad.
before you do anything with the alternator, make sure to unplug the battery. Then unplug the cables going into the alternator. There should be two. For the belt there is an engine part called a pulley - lift the pulley upwards to loosen the belt and take it off the alternator. Next you can unscrew the bolts attaching the alternator and take it out.
that light usually means that the battery is going bad or that your alternator isn't charging anymore
either the alternator is dischargeing the battery or it is going flat just because its not getting re charged
no, it would make everything in the car dim because of no charge going to the battery
Its going bad.
Sounds like the Diode or the Voltage Regulator is going out on the alternator. I would recomend replacing soon. When one of those 2 componets go out, it really over heats the alternator. This causes the bearings on the back side of the alternator to fail, and sieze. This has cause some fires in GM cars and trucks.
Thats going to be a dealer part for sure. Just got one myself