I just bought a bumper pull 20ft. x 8ft. all steel tandem axle trailer. I have electric brakes on both axles. My tow vehicle is a 2004 chevy w/ tow package. The brake controller is a tekonsha P3(fancy sucker) and it is plugged directly into the panel under the dash. My problem is that when I have the 6 way plug(trailer side) wired up to match the truck's 7 way plug via the adapter.. the brakes on one axle are locked down or I have no brakes at all. If, on the 6 way(trailer side) I unhook the supposed brake wire(white wire in this case) I can tow it.. but the brakes are still dragging ever so slightly. If I turn my blinker on and hit the brakes.. I can feel the trailer brakes surging with the pulse of the blinker and the marker lights on the trailer are pulsing with the blinker as well. As far as the tekonsha P3.. It will either say "short to battery" or "overload". I have one open spot on the 6 way that was unused. If I move the black wire over to that spot.. I get a "short to battery" msg on the P3. IF I leave the black wire in the spot that it was in when it came from the factory I get the "overload" msg. On the 6 way(trailer side), If I disconnect every wire except the white wire the P3 shows how much amps or volts(I can't remember) are going to the trailer brakes when I hit the brake pedal, but I do not have any trailer brakes. When everything is hooked up in the 6 way plug the way that it is supposed to be(as far as I can tell) All of my trailer lights work properly.

I have tried 2 different brands of 7 to 6 plug adapters with the same results. I suspect that it is something with the trailer wiring but I am at a complete loss. I have no ideas where to start in troubleshooting it. If anybody has any ideas, I would sure appreciate hearing them.

Thanks

IF I remember correctly there was a problem with the wiring at the remote fuse block on the 04 chevy's,call your local chevy dealer and ask them if they know of any bulletins on it.if not send me a pm with the vin number and i will try to run the vin tommorow to check for you ok.

Thanks stan.. I will give them a call in the a.m. if they are not any help.. I will send you a pm

thanks

I went by my local dealer and they didn't have any bulletins for it. I then went to a friend of my Father-in-Law's who does trailer repair. As it turned out.. it was the 7 flat- 6 way adapter. I went through two different brands of adapters(Hoppy and I think the other was Hopkins) He got one that he carries and plugged it in and it worked jsut fine... ugh.. at least it is now fixed. Thanks for the help.

i bought one the other day from tractor supply, exzakely the same problem thank china for that

ive had trailer plug come in my shop that were chinese and the position of the wires were off by one spot. everything is marked like it should be but it was rotated off one hole. talk about make you scartch your head.

for a second i thought you had a problem with your brake controller harness. GM pulled nice one on us when they switched the position of 2 if the wires in the plug. the the brake switch was replaced with the illumination feed. when you used an 03 model harness on an 04 truck and the auto headlights came on your brakes would lock up. very nice. thinking now it was 04 to 05.

Parker brings up a valid point as well as the fact that some 7to6 adapters are what we used to call Oklahoma style, where the center hot wire and the brake wire happen to be reversed. The only trailers I ever saw wired like that were WW brand trailers.

you must be in the same business as me or something close. WW is as assbackwards as they get from the brake wire position to the color codes of the wires. they have always been that way and im sure they dont plan on changing anytime soon.

I worked at a hitch and accessory shop in college. I learned a few useful tricks there I guess.