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trailer plug

Discussion in 'Ford Trucks' started by dodgegmc1213, Apr 1, 2015.

  1. dodgegmc1213

    dodgegmc1213 PlowSite.com Addict
    Messages: 1,011

    im changing the 7 plug on our 03 f450 since its been for ever and is corroded. I got 8 wires coming out of the harness of the truck, Im trying to figure out the electric brake wire. theres a smaller light green wire and a bigger blue wire and both read brake. as far as I know the blue wire should be for the brake but have no idea why the green wire is there. anybody with an idea or has the same thing? I believe no one added it so it must of came from ford like that. when we got our hitch plate welded on they added wire to the harness and used all one color so I don't know where it was wired to, plus inside the plug was a mess. most likely ok to just tape up the green wire and just use the blue wire? thanks
  2. flyguyirvin65

    flyguyirvin65 Member
    Messages: 57

    The blue wire is the electric brakes, the green wire will be the brake lights. They both are powered by the brake pedal but the blue wire carries more amps to the brakes
  3. dodgegmc1213

    dodgegmc1213 PlowSite.com Addict
    Messages: 1,011

    brake lights? they run through the turn wires tho.
  4. flyguyirvin65

    flyguyirvin65 Member
    Messages: 57

    it would be used if you had separate turn and brake lights. cap it off if you have brake and turn together
  5. dodgegmc1213

    dodgegmc1213 PlowSite.com Addict
    Messages: 1,011

    that's what I ended up doing, thanks
  6. kimber750

    kimber750 PlowSite Veteran
    Messages: 4,677

    Green is most often used for right turn/stop. Now most ford vehicles have a round plug that plugs into the backside of the 7 way plug. It looks like this. You can buy the trailer plug part and just plug the new one in.

  7. basher

    basher PlowSite Fanatic
    from 19707
    Messages: 8,993

    The blue wire is your trailer brakes. The green wire marked brakes is for a center mount stop light used if you add a truck cab, etc.