Hey guys I have a 2001 Chevy Monte Carlo SS with a voltage gauge issue. Now keep in mind that this happens when the car has been sitting in the hot sun or when the engine has been running for about an hour. What happens is that the voltage gauge will drop all the way down then come right back up after about 30 seconds to a minute. Of course when this happens my daytime running lights flicker, the AC compressor clicks on and off, and the factory radio goes into Lock mode. I have replaced the alternator (2 months ago) and the battery (5 months ago) yet I still have this problem. What could be causing this problem? It is hot outside and with black leather running the AC is a must, LOL.

 

Does anyone have an answer for me?

 

I know you replaced the battery and the alt, but it may be worth having them retested at the parts store (to ensure you did not get a dud). A bench test of the parts out of the car would be best.

Also check your wiring connections to the battery and alt for corrosion (if there is any, clean it with a wire brush).