dash problem

[NotchJohnson]

Hey I have a major bug inside my dash somewhere. Everything works just fine until I turn on the headlights. First, the dash lights dont work at all, but they do light up when I start the car and the headlights are not on. Also all my guages take a crap, and the tach flutters when I turn on a blinker. Also the turn signal indicators are always lit up when the headlights are on, but they arent on. The blue high beam indicator is lit when the headlights are on but turns off when the high beams are turned on. Does anyone have any idea what would cause this. I swapped all the switches with the ones from my 91 GT and all are fine. I also checked all the fuses and they are fine. I also went as far as to swap the alternator in case that was a problem and it didnt help. It drives me insane because at night I dont know how much gas I have, my temp, oil pressure, rpm and I cant see the speedo with no lights in there. HELP! Thanks, John