im not sure what the problem is. My lights dim below 3500 rpm and will brighten back up after 3500. Once it drops below 3500 it dims again. On start up on cold idle the lights are bright but rpms are 1200. Sounds like an altenator problem. BUT i have already went to advance and checked my battery and altenator and both tested perfectly. I also cleaned my battery terminal and gound wire. What else could it be?