Trailer wiring/electric brake questions

Discussion in 'Trucks and Trailers' started by Blyth, Dec 26, 2007.

  1. Blyth

    Blyth LawnSite Member
    from tx
    Messages: 37


    I am fairly new to the site. Usually, I just read and browse. I haven't even made that many post at all. Now I have a problem that I hope some of you can help me with. 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 TV'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 "no brakes" 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.

  2. topsites

    topsites LawnSite Fanatic
    Messages: 21,652

    All right here is what I think ...

    First off I find it disturbing that a 20x8 trailer would be called a 'bumper pull,' you don't per chance are referring to hooking this up to a ball attached straight to the bumper, are you..? Because I would think you need at least a Class-III hitch but probably maybe Class-IV, I'm not sure because I don't have that size of a trailer but I do know my 6x12 takes a class-III...
    I just don't think I would be for pulling that size off my bumper, to me those balls are more for 4x8's lol but really more like emergencies, I don't pull nothing with the bumper but that's just me.

    Now on the wiring...
    Your best bet in all of this likely is take it to a trailer dealer, they can wire it up right, also answer the questions concerning hitch, might run you several hundred but the problem is fixed.

    Unless someone has further input...
  3. Blyth

    Blyth LawnSite Member
    from tx
    Messages: 37 I am not pulling it off of the bumper.. that is just the style trailer. I am pulling it off of a hitch.
  4. bohiaa

    bohiaa LawnSite Fanatic
    Messages: 5,220

    sounds confussing:

    I too Just purchased a New to me trailer with brakes,

    my trailer had an owner that rewired everything and it was a mess.

    i simply got out the ole tester and trial and error and got it all working.

    I know this doesnt help ya much. other than hang in there.

    good luck
  5. P.Services

    P.Services LawnSite Fanatic
    Messages: 6,319

    ok this will solve all your problems in one move: bring it to me!!! that sounds like a fun one, i would love to fix it!!!

    start by hooking up to a diffrent similar trailer and see if it works. if it acts the same its your truck if it works then we will know its the trailer. thats the first thing to do.
  6. Albery's Lawn & Tractor

    Albery's Lawn & Tractor LawnSite Bronze Member
    Messages: 1,674

    Screw the adapters, spend $5 for the 7pin trailer plug and use it on the trailer and just match the wires to the wires on your truck. On the plugs they even tell you what wires go where.
  7. AllanAustreim

    AllanAustreim LawnSite Member
    Messages: 2

    You can buy testing tools at northern equipment that will allow you to test the truck and the trailer individually, which is very helpful. It could be as simple as two wires crossing somewhere, as that has happened to me before especially when the brakes are pulsing with the blinkers, I have had that before but I would take apart both plugs and make sure that there is good connections on both.
  8. hosejockey2002

    hosejockey2002 LawnSite Bronze Member
    Messages: 1,195

    As it seems typical, the longest reply is full of worthless information and the shortest one makes the most sense. Lose the silly adapter, wire the trailer to work with your truck.
  9. Blyth

    Blyth LawnSite Member
    from tx
    Messages: 37

    Thanks for the replys fellows. It was indeed the adapter.. I went through two of them before I found one that that I could just wire directly to the truck. All is fixed now. I am guessing the two adapters are s#@t. Anyway, thanks for the help. It is much appreciated.

Share This Page