I have a 1988 K1500 4x4 and just changed out the temp control and radio. I bought the temp control new and bought a CD player with adapter kit. I pulled all the old equipment regarding the radio out and wired into the harness provided with the kit. The radio works fine and the temp control works until I turn my lights on. I still have power and everything works but the temp control goes dark and now my gauges won't light up. I pulled the dash apart again and checked my wiring and unplugged the new temp control and my gauge lights still don't work. Any advice on why I lost gauge lights and why the temp control lights up with the lights off, but goes dark when I turn on my lights would be greatly appreciated..

 

Bad ground to the cluster.

Allan