4 wheel drive gmc sierra 1500 1993. the cigarette lighter, radio and inside cab light suddenly don't work. is there a relay or fuse in engine compartment i could look at?

Your fuse panel is either under the dash by the drivers left knee or on the side of the dash where it meets the door. the radio fuse should be the second from the top right side of the fuse panel. its a 10 amp fuse. the power for the switch should be a 16 gauge wire run from the passenger firewall (under hood.) behind a plastic cover where a lot of wires are bolted to posts. that red wire feeds power to almost everything in the cab. it runs behind the glove box and has a disconnect there. if the fuse is not bad and the wire looks good, check the ground on the passenger door "open switch" (the one that is supposed to turn on the dome light. that is where the whole system is grounded for the int. lights lights