Trailer Lights not working (GRRRRRRRRRR)

[CRATUS]

Hi.

I have been fighting a losing battle with my trailer lights...

the lady who had the truck before me, drug the plug off the bumper,
so I bought a new one and put on the truck,
before putting it on I checked the wires and they were dead,
well after a blown fuse later they were working so I put the new plug on and tested with a light, all is well, I go to plug the truck to my enclosed and nada, nothing, testing with a light I get nothing, no blown fuses and I can hear the relay's under the hood when the turn signals are on...
I checked the harness plug around the spare tire, it seems to be connected and in good condition....

any other idea's

[Nashotah7]

Sounds like a bad ground somewhere, either on the trailer or the truck.

[CRATUS]

yeah, possibly the truck,
I have 2 trailers and another truck, I pulled both trailers over the weekend and they worked great,