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GMC Ultramount Light question

Discussion in 'Truck & Equipment Repair' started by muddy00, Nov 14, 2004.

  1. muddy00

    muddy00 Member
    Messages: 34

    Just got a used ultramount for my 2002 gmc 2500, all seems to be ok (except for a missing mount part) but I have no low beams, park lights and high beams work but neither low beam, could both relays be bad?
  2. Frozen001

    Frozen001 Senior Member
    from Rome NY
    Messages: 908

    Daytime running lights question(2004 GMC Sierra)

    I don't have an answer, but I have another related question... I moved my plow (a new 8' western pro ultra-mount w/the isolation module) today, did some final adjustments, and I hooked up the wire that runs the daytime running lights(DRL) (my dealer did not hook them up which he told me btw, said some people like it some do not want it forgot to ask me before I left when I dropped it off, so I just told him I would hook it up). Any way, the plow lights do come on with the DRL, but the plow lights are very dim compared to when I switch on the head lights. Is this normal???
  3. sonjaab

    sonjaab PlowSite.com Addict
    Messages: 1,425

    MUDDY..Go to the http://www.westernplows.com
    They have a guide which should have your wiring diagram. Its PDF format.
    Very handy to have.
  4. Garagekeeper

    Garagekeeper Senior Member
    Messages: 459

    Jeff what year truck did the wiring come off of?
    They are differant between years due to GM changing bulb polarity and the way they switched them on, you may need more then two relays or the harness connector polarity needs to be changed.
    It's getting harder to swap plows and harnesses, so you will have to identify which wiring system you have.
    :rolleyes: John..................
  5. muddy00

    muddy00 Member
    Messages: 34

    It came off a 2001 GMC yukon, from what I could tell they are the same
  6. sonjaab

    sonjaab PlowSite.com Addict
    Messages: 1,425

    GUYS......I just had my Western swapped from my 01 to my 04 Chevy.
    I had to buy a new wiring harness, plow lights, and go from relays to the iso. module.
    Truck side is done..........

    I have to bring the plow to the dealer to install new plow lights and plug.
    (Already paid for anyway)

    Funny tho...Everything works except the hi-beams.
    Dealer sez they wouldn't .

    Keeper..You are correct again !

    Question: Could I swap a wire or 2 on the existing plowlights to make them work ?
    Dealer will NOT "cob" or change existing wiring for the old lights to work. Says he don't need the "headaches or comebacks" down the road.
    Don't blame him...............
    He will refund the new plowlight $$$ if I want to change the wires myself.

    I have a test light and such and should be able to do it myself.........

    Thanks if ya can help..............geo
  7. Crash935

    Crash935 2000 Club Member
    Messages: 2,377

    Muddy, i'm working on your problem, will get back to you.

    Frozen, yes that can be normal, Drls are actually supposed to be at a lower intensity.

    son, no you cant really just swap some wires, GM went to a seperate wire and fuse for each headlight bulb and because of the size of the curcuit and the size of the wires to each bulb you would end up blowing fuses or melting down your harness if you just tried to jump things.

    Muddy, back to yours, If your relays are set up in the 2x3 block you should have the plow low beam, truck low beam and the drl relay all in a row, There needs to be a diode between the plow low and the drl relay, if not, you get back feed up the ground leg and it cancels out the lows. Also, did you hook up your drl tap at the blue wire to the bulb next to the turn bulb?

    Check those and let me know.
    Last edited: Nov 15, 2004
  8. muddy00

    muddy00 Member
    Messages: 34

    It was a bad relay on the plow side, thanks for the help :redbounce

    LET IT SNOW!!!!!!!!
  9. sonjaab

    sonjaab PlowSite.com Addict
    Messages: 1,425


    I pulled my old set off. I am gonna compare the wiring set up between the 2.
    Want to disassemble each headlight (old/new) .................

    Might get lucky and be able to test/check the difference and switch a wire in the headlight internally and not cob/cut the outer wiring plug assembly.

    $217 bucks for new lights is pretty $pendy considering the new truck side harness and iso. module was $254.

    Having a 'puter prob. with the Western sites PDF.................geo
  10. Frozen001

    Frozen001 Senior Member
    from Rome NY
    Messages: 908


    Thanks for the info.... I figured that was what was suppose to happen, but no having seen them bofore I wanted to make sure...
  11. snsauto

    snsauto Junior Member
    Messages: 1


    To both of you, i am a Western Dealer and first address the no low beams, can you tell me what number is on the headlight harness. Chevy made so many changes each year for the last 5 years in their electrical system that if you do not have the correct harness, those light will not work, even though they plug in.
    As for you Daytime running lights they are light sensitive, so they will get brighter as it gets darker.
  12. Frozen001

    Frozen001 Senior Member
    from Rome NY
    Messages: 908

    Thanks for the info!!!
  13. bwbigred

    bwbigred Member
    from nj
    Messages: 31

    im having the same type of issue and i am lost its an 02 gmc truck right now the pink drl wire is not hooked up which wire do i hook that to...... with it not hooked up i have no plow lights but when i turn high beams on they are fine what should i try my isolation module is brand new and so are my turn light harness wires truck side?