Dimming headlights and interior lights?

[bryanf89]

dude i had the same problem except i had a new alternator...i thought i had a short circuit since the battery would end up dead sometimes...it ended up being the pulley...i had to put a tiny pulley because according to gear ratio, the smaller the pulley the more revolutions its makes with one spin of the crankshaft...that pulley cured the problem

[btwilson86]

Changing the pulley could make it work for awhile, but that's nothing more than a band-aid. Spinning the alternator faster to compensate for an improperly working part will just put more stress on other parts of it, such as the bearings, causing it to fail early.

bryanf89, I suspect your new alternator was defective from the start (every manufacture has a certain percentage of defective parts).

I would suggest that both of you take your alternators (with the factory pulleys) to an auto parts store near you and get them tested. Also check the wiring coming from your alternator to make sure it's not old and brittle, as this can cause poor charging. If you have a voltmeter, you can check the voltage at the positive lug on the alternator and a chassis ground. With the engine running, you should have around 13.5 volts. Now check the voltage at the battery (still with the engine running). If the voltage deviates at all, you need to inspect/replace your wiring.

Let us know what you find