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Trailer harness Aux. Power

Discussion in 'Chevy Trucks' started by lawnMaster5000, Dec 12, 2004.

  1. lawnMaster5000

    lawnMaster5000 Senior Member
    Messages: 105

    I have done several searches on this and can find a few discussions but never an answer so i was wondering if someone could help me out.

    I have a 2000 GMC 1500 with the factory 7wire trailer harness. In that harness everything works properly EXCEPT the positive lead for accessories. I have already connected my brake controller, which was pretty easy.

    I understand that there is either a fuse i need to install or an additional harness for in the cab but i cant find the information on what to do and how.

    There is a discussion of a similar problem in this thread

    Please help me out for I have a trailer that needs to run lights off this circuit and I would like to be able to run aux back lights from this plug also when plowing. That way i can just run a low power relay wire into the cab, and not have to run anything to the battery.
    Thanks for your help.
  2. sonjaab

    sonjaab PlowSite.com Addict
    Messages: 1,425

    Scott......look in your underhood fuse center. You will have to install a fuse to get HOT power the trailer wiring harness. The fuse is omitted from the factory..........

    The lug #s and size of fuse should be printed in your owners manual.

    I can't remember offhand which #s...........
    Check gm-trucks.com or pickuptruck.com for a sticky post on what ya need to do............This will be posted in the maint. or help forums..........

    Or somebody will post the answer here shortly !.................geo :drinkup:
  3. Tarkus

    Tarkus PlowSite.com Addict
    Messages: 1,113

    It is near the brake master cylinder on firewall and it "should" be 30 amps but mine was not hooked up from factory (wire was stowed nearby) but fuse was present.
  4. redhenny16

    redhenny16 Senior Member
    Messages: 134

    It should be the 40 amp maxi fuse that goes into the stud #1 location in the under hood fuse block.
  5. lawnMaster5000

    lawnMaster5000 Senior Member
    Messages: 105

    Thanks for all the help guys. I think I know what to do now, pretty easy. why cant the owners manual just say what redhenny said ???
    Now i just have to find somewhere that actualy sells the 40amp fuses, I guess I am going to the dealer in the morning.

    thanks again,
  6. Tarkus

    Tarkus PlowSite.com Addict
    Messages: 1,113

    Do they have a Napa or Advanced Auto or Auto Zone where you are? They would likely have them.
  7. sonjaab

    sonjaab PlowSite.com Addict
    Messages: 1,425

    SCOTT...You could also try a RV/trailer dealer or a trailer hitch installation place. They know what ya need........

    FUNNY........Some years HAD the fuse and lug stashed in the underhood fuse center and not hooked up. Other years didn't ..............geo