check all your wires/connections to your trailer wiring. if there is a short there, itll pop your dash lights, and sometimes your tail running lights as well.
i had this situation when i bought my truck. had no running lights (brake, turn, headlights fine) and no dash lights. tried replacing the headlight switch in the dash, still no dice. turns out the guy before me had a ball in the bed setup, which he removed, and simply cut the wiring raw which was running to it. this was left to rest in the inner fender. a tiny bity teeny wire from the cut end was grounding. was so weak that it didnt blow the fuse, but caused the contacts in the fuse box to corrode/arc. cleaned up the wiring, and the contact in the box and pow, all lights worked.