I have a 1974 Bonair 1200 tent trailer. Got it last year. When I bought the trailer, previous owner said 2 of the clearance lights were not working and he did not get around to replacing them. He gave me replacements though. I intended to replace them this year. This year none of the clearance lights work. I checked the lights and bulbs are fine. I bought a couple replacement light assemblies, standard and led, and installed them. Does not work. Checking further I see I have brake and signal lights, but don't seem to have running lights. Not even sure if I ever did now that I think about it. Previous owners kept the trailer in excellent shape and repair, elderly guy who appeared meticulous with everything, so I suspect the issue may not be the trailer. Maybe. The hitch and wiring on my van were installed by Uhaul 7 years ago and there were issues with the install (wrong one installed). I did not use it at all until 4 years ago when I hauled an enclosed trailer and noticed I had no running lights and the brake lights did not work if signal lights were on. Trailer owner said he had lighting issues so I ignored it. Was just using it for 2 hours. A couple years later borrowed another trailer, just a tiny utility trailer with brake turn lights. Lights worked fine, no issue. In the van is a 4 pin connector with green lights that I was told by Uhaul turn on when plugged in to show all is well. When I plug in any trailer I never see any green lights. 3 different trailers, no green lights. How do I check my connector, and if it is good what else can I check?