1. Welcome to PlowSite. Notice a fresh look and new features? It’s now easier to share photos and videos, find popular topics fast, and enjoy expanded user profiles. If you have any questions, click HELP at the top or bottom of any page, or send an email to help@plowsite.com. We welcome your feedback.

    Dismiss Notice

04 2500HD Wiring

Discussion in 'Chevy Trucks' started by Motorman 007, Jan 11, 2005.

  1. Can anyone tell me where GM hides the termination to the pre wired roof light circuit included with snowlpow prep package? The truck is an 04 2500HD crew cab. When I activate the dash switch I can hear a relay clicking in the drivers door post, but i want to be sure. Thanks in advance!!

    MM007 :salute:
  2. Frozen001

    Frozen001 Senior Member
    from Rome NY
    Messages: 908

    Check out http://www.gmupfitter.com
    Look under publications....technical bulletins....#27

    Shows location of the wires. Out can also get at them in the rear driver-side cornet of the truck.
  3. ratlover

    ratlover PlowSite.com Addict
    from IL
    Messages: 1,325

    you can run it out from under the 3rd brake light or run it down and out the little plastic vent/grill between the bed and the cab so you dont have to drill.
  4. carlriv2

    carlriv2 Senior Member
    from Mass
    Messages: 126

    Is the roof wire inside the pilar behind the drivers door, or the back door on a crew cab? I would like to mount a power supply for hide away strobes under the back seat, and I would like to find the wire the first time. I assume the the relay is near the front?


    I did not say the truck I need to find the wire in is a 2006 silverado crew cab.
  5. sonjaab

    sonjaab PlowSite.com Addict
    Messages: 1,425

    CARL.............The wires are heavy brown + and black- are
    deadheaded in the headliner on the front left side of the truck
    over the driver.

    The relay is in the left rear B pillar (corner between window and
    door) behind the plastic trim piece.
    The wires run from the floor up to the relay (near the shoulder belt
    bolt) then continue and deadhead in the headliner.

    Take off the seat belt and trim panel. Or if you can just get the trim
    panel loose some then just pull the wires back down to where you
    need them.

    If there is NO power at the switch or relay you may need to put
    a maxi fuse in the STUD #2 slot in the underhood fuse center.
    Sometimes GM forgot...........................geo
  6. carlriv2

    carlriv2 Senior Member
    from Mass
    Messages: 126

    Thanks for the reply. I am not sure what the B pilar is on a Crew cab. I will check for the fuse, and see if I can hear the relay click. I have done hidewaways in a 2000 regular cab, and 2000 extended cab, but the crew cab has 2 pilars on the drivers side (one for each door).

  7. It's in between the front and rear door

    It's in between the front and rear doors in the pillar on the drivers side up high, tucked under the headliner. The relay clicks in there when you activate the switch. I did exactly what you are looking to do. Once I located the wire, I just untaped it and removed it from a couple of plastic connectors and ran it down the pillar and under the driver side rear door kick panel and behind the rear seat to power my Whelen tail light strobes. Good Luck.
  8. ratlover

    ratlover PlowSite.com Addict
    from IL
    Messages: 1,325

    Worse case hit the button a few times and listen for the clicking. That will be were your relay is hiding ;)
  9. carlriv2

    carlriv2 Senior Member
    from Mass
    Messages: 126

    Thanks, I found it. It is in the same pilar, right behind the drivers seat. I pulled all the wire out of the headliner, and ran it under the trim. I had enough wire to reach under the middle of the back seat. Perfect spot centered in the truck, and well protected.