wow this is almost the same exact problem i'm having right now.
i recently installed a new cd player. after i hooked everything up it seemed like there was something screwy going on with it. if i hit a bump it would go off. then it would only come on if my running lights or head lights were off. then only if the lights were on. then on monday i was driving and i hit a very small bump and my dash lights and cd player went out. if i take the tail light fuse out the stereo will come on. but then it will turn off as soon as it tries to read the cd. i replaced all the fuses and still the dash lights wont come on. then yesterday i tore apart the entire dash to try and see if i could find a wire that might have come loose. still no luck though. i don't have anymore ideas as to fix the dash lights or the stereo.