What kind of truck do you have? I know that the newer chevy's have a fuse under the hood that will make you run in circles all day, if you dont know about it. I suggest hooking up the trailer to a different truck, if it works fine, I am gonna suggest checking the fuses under your hood! There are like 3-4 different trailer fuses under the hood, I am willing to bet this is your problem! Hope this helps. If you have questions about the fuses email me and I will call you back. Good Luck!

Well, did you get it figured out?

I thought I posted this already, but I must have been dreaming. Anyway, check this site out:

http://www.accessconnect.com/trailer_wiring_diagram.htm

You probably just missed something. Been there, done that.

the trailer lights are self grounding. you should hit the surface of whatever they mount to with a wire brush and screw them back on tight. mine were doing the same exact thing.

Hey be sure to check all fuses dealing with the lights on the truck. I had this problem before with brand new lights and wiring. Talk about drive yourself crazy and the whole time it was a stupid fuse. It seeems to be a common problem with the newer GM vehicles because my dad had the same issue. I now keep a box of fuses in my vehicle at all times.