I installed my factory hitch and the wiring harness but figured the last couple of times, the trailer had a dead bulb. So, here I am, 4 years later, and U-haul wouldn't rent to me. I only rent a trailer occaisionally and realized the same issue you are having. I went through the wiring diagram, labeled everything, tested everything and realized, the gray, turn (right) input, supply line is NOT LIVE, with the turn signal on. So, the blue wire is hot, the gray is dead. Did the factory forget to hook this wire up and if so, how far to the front of the vehicle do I have to search for this disconnected wire? Maybe I have to go to the passenger side or in the fuse box somewhere???? Any help or link would be appreciated.
