89 seville electical gremlin

1989 Seville with a 92 4.5 litre engine installed. Ran great forever in a day and then one day driving along and the digital dash and driver info panel goes blank, like it lost power; but the car doesnt miss a beat and keeps on going like nothing is wrong......frustrating as it is I have checked my ground wires, done the ole' wire wiggle check and have been chasing wires for chaffed wires, shorted out, and just checking everything. I am stumped, and when the lights and stuff does kick back on the A/C automatically comes on with out it being selected at all.....Please send help, or some sort of answer .......Thanks