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'04 GM Snowplow Prep Beacon harness...

Discussion in 'Commercial Snow Removal' started by TLS, Mar 12, 2004.

  1. TLS

    TLS PlowSite.com Addict
    Messages: 1,425

    On the Snowplow prep package trucks, I heard the switch on the dash activates a harness tucked up above the headliner for those that want to drill a hole in the roof of the cab for a beacon.

    Obviously, I don't want to drill no holes.

    I just installed a BackRack and will be mounting a single beacon on the top center of the Backrack. Would really like to use the factory dash switch, but wonder if I will be able to get to that wire loom up there.

    Took off my 3rd stoplight/cargo light and looked.....nothing there! Matter of fact about 3" in from that opening is a sheet metal "wall" or baffle that is slightly angled. I'm assuming that the wiring loom is behind this?

    Any ideas guys?

    Or would it be better to somehow tap into this switch feed and run a stand alone wire up between the bed and the cab and up the BackRack?

    I would also be putting two flood lights on eigher side of the BackRack. Would also like to use the dash switch for the back cargo light to illuminate these? Any suggestions here? Maybe make that cargo light switch activate a relay, and run a good sized wire to them, as the wiring for the cargo light and stop light are VERY tiny...like 18-20 gauge!

    Any tips would be helpful!
  2. ratlover

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

    The relay aproach is what I would do for the flood lights. Sounds like you got it nailed on that one, just run some 18 guage or so from the cargo lamp(dont need to go from the switch) into the relay and you will be set. I have the relay and all that in my tool box in the bed of my truck(I have a relay on my reverse lamps so my other ones on the light bar light up)

    You have to pull the headliner down on my 03 to get to the loom. Found the 2 wires taped together, fished em out the hole for the 3rd brake light, then I ran it out under the 3rd brake light and screwed the 3rd brake light back in place.
  3. Turfmower

    Turfmower Senior Member
    Messages: 376


    PROPJCKEY Senior Member
    Messages: 125

    I hace an 02' HD2500 and do use the dash switch. All I did was drill a small hole (carefully as not to crack the plastic!) iin the BOTTOM of the cargo lamp. Installed a small rubber grommet and tapped into the white (cargo lamp) circuit. Granted, the cargo lamp is on when my stobe is on but, so what!? More light is always better than not enough. It is not drawing enough amps to cause any electrical drain. Also, I found at NAPA a small two-wire quick disconnect that I mounted to hang out of the lamp just an inch or two so I can remove it in the summer. Will try to post a pic if I can find my digital!
  5. sonjaab

    sonjaab PlowSite.com Addict
    Messages: 1,425

    TLS..........Sorry that GM upfitter link is dead now.
    I have a newer link ...but can't find it at the moment.

    If you have a reg.cab take off the piece of plastic on the left
    side next to the back window. All the wires run up that way.
    You will be looking for a heavy brown + and a heavy black -
    You can take off the brake light and fish them out that way.

    The steel in the roof is just a support rib. Its tough removing
    the headliner cuz if ya break those cheap clips....BUMMER !

    If you have a x-cab you can pull the headliner down GENTLY
    on the left side and fish them out.

    Or you can pull off the overhead console (1 screw holds it on)
    and fish them outta there.

    I have a ex-cab and put male/female ends on the wires and my
    magnetic strobe. I just feed the plug out thru the back door.
    Plug in when plowing (NYS law). Unplug and tuck the plug
    in the headliner when not needed...................

    There were a few pics a few guys took . They ran their wires
    out the 3rd eye brake light. Do a search in the GM truck discussions here. you will find them.........

    If ya need a print out of the GM upfitter site ASAP shoot me a email and I will mail ya a copy.

    I will dig up the new upfitter link and post....................geo
    Last edited: Mar 12, 2004
  6. Winterworks

    Winterworks PlowSite.com Veteran
    Messages: 97

    We have several GMCs with the plow prep. Find find the brown and black wire as sonjaab posted, and run it out the cab vent on the back wall of the cab. Ou mechanic tells me it is pretty easy to do.
  7. PLOWMAN45

    PLOWMAN45 2000 Club Member
    Messages: 2,951

    there is a company called painless wireing might wanna check the web
  8. sonjaab

    sonjaab PlowSite.com Addict
    Messages: 1,425

    PAT............Barrie Ont. eh?
    Grampa and dad born and raised there ! Still have some family
    there also. Been to Wonderland lately ?

    We own a summer motel in the 1000 Islands near Alexandria
    Bay NY on the US-Can. border. We go to Gan. and Kingston a lot!
  9. ratlover

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

    Winter works> EXCELLENT IDEA! I might have to do that to "clean things up" a bit.
  10. TLS

    TLS PlowSite.com Addict
    Messages: 1,425


    Found the wires for the OEM Beacon setup.

    Ran them out the rear cab vent.

    Nice clean setup.

    Still didn't address the rear facing utility lights as of yet.

  11. sonjaab

    sonjaab PlowSite.com Addict
    Messages: 1,425

    TLS..........Glad ya found it ! Easy huh?
    Heres a new GM upfitter link. But its PDF now and ya gotta search it !.............geo


    Look under publications...Lots of stuff there for PTOs and other
  12. sonjaab

    sonjaab PlowSite.com Addict
    Messages: 1,425