Sorry for the multi-posts. Keep getting interrupted. If it is your dash lights that are out, they get their voltage from the same tail light relay, so sounds like that 15A fuse, the tail light relay, and the light-combo switch are the common points. The light/combo switch provides a ground to operate that relay. If the relay isn't working, to check the switch, pull the relay out. the pins are numbered
3
1
2
if you look at the plug the relay came out of. 1 should go to ground when the comb switch is turned on. 2 should be 12V, and 3 goes to that 15A tail light fuse.