This sounds stupid, but every day I take it inside to try to figure out what the hell is wrong with it. After I leave it pluged in for like 5 minutes on AC power (and adjust the dimmer about 100 times to see if its working right or not )with it forced to DC mode, the dimmer clears up and starts working, then the next morning it just gets screwed up again. Maybe my car stereo only likes the AC adapter or something.... I tire of this!