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Trailer Wiring Plug Question

Discussion in 'Ford Trucks' started by trip5981, Apr 1, 2010.

  1. trip5981

    trip5981 Junior Member
    Messages: 8

    Hello, I have a 06 Ford F-250 SuperDuty Diesel. Im wiring a 7 plug trailer harness on a trailer. The truck came factory with a 7 & 4 plug hook on the back. The problem I am finding is I only have power to 4 of the 7 wires on the back of the truck (brake, signals, & markers/tails). I feel like I am missing something as simple as adding a fuse but I'm looking for input from you guys that probably know. As always Thanks in advance.

  2. .5racer

    .5racer Senior Member
    Messages: 132

    Have an 01 F150 and the other three are ground back up aux power . And the power doesn't come on ,on mine till the engine is running . Wont draw truck down that way, say with a winch on the trailer ,so you can START the truck.
  3. basher

    basher PlowSite Fanatic
    from 19707
    Messages: 8,990

    you could be missing the relays and fuse from the power distribution box under the hood. The fuse is in the big box the relays have a little box of their own. there should be a piece of black electrical tape on the little box if it has not had the relays added yet.

    The 12 volt will not operate unless the switch key is on.

    The brake signal wire will not have power unless you have a brake control and some one manually engages it.

    the 7th wire is a reverse light and will not light unless you but the vehicle in reverse.
  4. SteveR

    SteveR Senior Member
    Messages: 252

    Should be one for trailer brakes also, If you dont have the built in control you need to add the pigtail and install the relay under the hood.
  5. Mnpowerstroke99

    Mnpowerstroke99 Member
    Messages: 82

    X2,check the power distribution box under the hood
  6. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    Look at the wiring diagrams in a repair manual. It should explain the wire colors at least.
    The Library has pro manuals too,or can point you to one that does..