I have a 87 GTA with digital cluster. The cluster and everything lights up, untill I turn the headlights on. With the headlights on my cluster is still light up and I can dim it, but the radio display goes blank, and no other dash lights come on. I have checked the bulbs, fuses and grounds and they are all good. I have owned the car for a little over a year and the dashlights have came on once while I was at a stop and stayed on all the way home, but have never cane on since. Are there any other switches or relays that could be bad? I am stumpped.