Originally Posted by robo59097
Now that I think about it your right, I was thinking on the rental trailers we use to have we ran a separate ground that required the trailer to be hitched
Sorry I confused things. I definitely just have a 7 pin connector. When I was pulling the trailer, the brakes worked but the lights did not.
When I got home, I took a simple 12v testor and checked power coming from the truck. With the emergency flashers on and grounding the testor to the body, I confirmed power from the two pins (6 & 5/yellow & brown). I then took the sheath off of the 7 pin connector on the wires coming from the trailer. I took each wire loose cleaned them up and reconnected them. I then did what I could to clean the contacts in the plug. I was able to get power on 6 & 5 on the trailer side with the ground from the testor connected to the truck; however, the lights were still not working. I then hooked the trailer via the hitch and I had lights.
I feel pretty sure that ChooChooMan74 is correct. My trailer is not at my house, so I wil do as he suggested when I get back to the trailer. It does seem weird that the brakes worked and the lights didn't - I agree, if the ground wasn't connecting through the white wire from the truck, it seems that the brakes should not have worked either.
So, if I do the diagnostics suggested by CCM74 and I find the ground is the problem (which I suspect), how do I run a new ground. The white wire going to the trailer is in the bundle of 7 wires. Do I abandon the white wire in the bundle and run a separate wire? And the biggest question that I still don't understand is: Where does the white ground wire in the bundle connect to the trailer? I assume it connects to the frame somewhere? I am hoping that that connection has just come loose and I can reconnect it, negating the need to run a totally new wire.
I really appreciate your enthusiasm for helping me out.