Dash lights and tail lights on 1999 Mercury Sable dont work

I checked the fuses in engine compartment, they are good. Car does not have auto lights. There is no power on the dash light and tail light fuses inside of car in fuse box. I put a jumper wire from cigar lighter to fuses and lights will work. I can hear a relay kick in when I touch the jumper wire to the fuse. Sounds like its coming from behind the radio/ heater control unit. Any advice for me? Thanks