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Trailer Lights and Brake controler not working

Discussion in 'Truck & Equipment Repair' started by tpost, Feb 5, 2009.

  1. tpost

    tpost Junior Member
    Messages: 3

    My 03 GMC 2500HD trailer plug and break controler are not working. My break controler does not even light up when i apply the break. I replaced the hoppy plug with a new one still no go.
  2. no lead

    no lead PlowSite.com Addict
    Messages: 1,308

    pull the 7way plug apart and see if its all corroded . is this the hoppy plug you mentioned?
  3. wild bill

    wild bill PlowSite.com Addict
    Messages: 1,239


    just the brake function? do lights on the plug work ?check all trailer fuse's under the hood ,check the power wire for the brake control ,see if it is broken ,disconnected ,circuit breaker or fuse ,tripped,or blown .
  4. Dustball

    Dustball Senior Member
    Messages: 274

    Possibly a problem with your brake light switch on the brake pedal. If that doesn't work, you don't get brake lights or a functioning brake controller.
  5. CityGuy

    CityGuy PlowSite Fanatic
    Messages: 17,220

    If its an add on I'll bet that you fuseable link has gone bad
  6. tpost

    tpost Junior Member
    Messages: 3

    I've replaced the entire plug.
  7. tpost

    tpost Junior Member
    Messages: 3

    It is not an add on came from factory. I guess i am just not sure where the fuse for the trailer lights or brake controler are. The inside fuse box is labeled 10amp trlr i've checked the four of those and they are good.
  8. unit28

    unit28 PlowSite Fanatic
    Messages: 6,634

    under hood fuse is blown?

    welcome to Plowsite!

    the place of many inteligent answers...the questions are a different story though...LOL j/k
    Last edited: Feb 6, 2009
  9. ahoron

    ahoron Senior Member
    from here
    Messages: 422

    Fuses under hood on drivers side should have several for trailer the trailer brakes are the big front one, I believe, I installed trailer brake controller to that one in my truck not sure about factory think it's same not sure
  10. nbenallo33

    nbenallo33 Senior Member
    Messages: 826

    it should be a pal fuse under the hood
  11. no lead

    no lead PlowSite.com Addict
    Messages: 1,308

    is the brake controll mounted on the dash? or is it in a panel in the dash/recessed?
    did your 7way plug bolt to the truck or in a bracket welded to the hitch?

    SNOWPIMP Member
    Messages: 89

    ditto I have installed/fixed over 200 of these in the past 2 yrs (I deliver new boat trailers from the factory for a friend that owns the factory) and the brake light switch power feed comming into the controller was ALWAYS the problem with the symtoms you describe. Only 1 time was it ever the controler itself and that :angry:OF COURSE was on my truck not a customers!!!!!
  13. tawilson

    tawilson Senior Member
    Messages: 225

    Trailer lights don't work either?

    SNOWPIMP Member
    Messages: 89

    trailer AND truck brake lights. That would be my guess sometimes you just don't notice the "small" stuff like that unless you know what to look for!
  15. basher

    basher PlowSite Fanatic
    from 19707
    Messages: 8,993

    Fuse problem for sure. Power disturbution box under the hood on the drivers side.
  16. tawilson

    tawilson Senior Member
    Messages: 225

    If the truck brake lights don't don't work also I'd be checking the fuse for that.
  17. horsepowerlawns

    horsepowerlawns Member
    Messages: 97

    Look and see if your CHMSL (center high mounted stop lamp) comes on when you hit the brakes.
    That fuse is the one that feeds the brake control when you hit the brakes. If its that, the fuse its under the hood or on the drivers side of the dash (open door and look at the side, NOT UNDER the dash.

    You didn't say what kind of control you have, you may need to relevel it.