97 Chevy Blazer HELP!!! NO TAIL LIGHTS
 

1997 Chevy Blazer LT 4 x 4 4.3 l trying to sell the car but I can't because the running lights are inop. I have changed the multifunction and the headlight switch and replace the brake switch. As far as I can tell there are no blown fuses and I replaced two relays j in the fuse box in just case. I have also replaced the 3 relays in the glove box. My instrument cluster light doesn't come on and my 4 by 4 control is inoperable. My stereo has power... but no audio. From other forum posts I've heard that it's the tccm for the 4*4 issue I went to Auto salvage and bought two TCCM's and have had no changes with my 4 by 4 controls please help