Trailer Wiring Diagrams Pinouts

Discussion in 'Towing & Trailer Tech' started by Cableguy, May 9, 2007.

  1. 03 SIERRA

    03 SIERRA Rockstar 100 Posts

    i work at a trailer shop and ive seen it a couple diff ways. i havent done it on an 09 but on a 99-06 you have to pull the under hood fuse block apart and there are 2 eyelits haning around in there and 2 empy studs on the block. one brake controller and another 12v put 2 and 2 together add fuses if necessary and vwalw. hope this helps
  2. Crockett

    Crockett New Member

    Trailer Plug Problem

    I have the same problem with my trailer plug on my 2004 Sierra 1500
    No R/H Signal, No Aux Power.Truck lights all work fine.
    Seems like a common problem.
    Anyone got any ideas ?
  3. shadowt_t

    shadowt_t Epic Member 5+ Years 500 Posts

    thanx for the diagrams
  4. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    Check the fuses that power your trailer wiring.. I have had the same problem on a few of my trucks and since there are up to 4 fuses powering your trailer something to look at.
  5. Crockett

    Crockett New Member

    Thanks For the reply Murdog94
    I have checked the fuses in the main Fuse Block before posting and everything looked ok.
    I was thinking maybe a loose connector somewhere along the harness but i havent managed to find it yet. It looks good at the rear of the trailer jack. I think i am going to have to find a wiring diagram to troubleshoot it further. Any suggestions are appreciated.

  6. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    Ok not trying to beat this one up i know that in some trucks that there are two fuse blocks and that there are fuses in each block.. and if you have a loose harness id check right in back where the wiring actually connects together to allow for the trailer harnes first...
  7. ChevyFan

    ChevyFan The Sheriff Staff Member 5+ Years 1000 Posts

    Wow, such a shame that people LINKED to photos for this thread instead of uploading or attaching photos to GMTC where they can stay forever. Great thread.
  8. bbissonn

    bbissonn New Member

    great diagram - does this diagram work with all brake controlers.
    I have a prodigy electronic brake controler and have just purchased a new 2012 gmc sierra denali and can't seem to find the wires under the dash or a wiring schematic. The tech from the dealer is on vacation and nobody has a clue where to look. I assume the wires are taped up under the dash and I will keep looking. Do the wire colors match up for the prodigy brake controler. TGhe colors for the prodigy are black= +12 volts, red= stop light, blue =trailer brakes, and white = ground. As soon as I find the wires under hte dash I hope the colors match up. Any guidance would be helpful Bdog
  9. jake's silverado

    jake's silverado Epic Member 5+ Years 500 Posts

    Send me a PM with your e-mail address and I can send you a pdf file that may help you. I tried to post it here but it is to large. I also have it as a powerpoint that shows the wire location under the dash and under the hood. It is for a 2007 NBS but I don't think much has changed for this.
  10. bbissonn

    bbissonn New Member

    trailer brakes

    Thanks Jake,

    My email is bbissonn[MENTION=31637]gma[/MENTION] Hope you can help.


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