The lights (headlights, dash lights) dim greatly at idle, and then brighten back with any increase in idle on my mostly stock '89 Diplomat police car. There is a bit of flickering too. When I first got the car I immediately had the alternator rebuilt because car had sat so long and I didn't want to chance it. I also have replaced the voltage regulator. I really don't know if it was doing this before I replaced these things because I didn't drive it at night prior. The battery cables look fine, and I cleaned the ground cable to the block real well. Seems to be charging ok, but continues to dim and flicker. It is the 100 amp police alternator, and it does this even when the only thing turned on is the headlights. My others don't do this. It is a very noticable dimming/brightening/flickering. What to I try next? Thanks.