Mine would blow out the fuse for the dash lights anytime i would use 4wd.It was the wiring harness that had the 4wd.indicator for the dash light, the wiring had a small tear and would ground out when shifted and kill the dash lights. Sounds like your problem has to do with the trailer wiring harness but may wanna check around the T-case too, dealer did mine under warranty when it still had it. I've dragged my hitch around alot but had no problems from that yet.