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new headlights, no work

Discussion in 'Western Plows Discussion' started by wls, Nov 23, 2011.

  1. wls

    wls Senior Member
    Messages: 319

    Last nite decided to put new lights on the plow, cut the main harness, found all the corosponding wires to there function, hooked them temp to make sure they worked, they did. today went to hook wires together permenant, did that, now pull the lights on, truck side stays on, the only lights that work is the blinkers, on both sides, (still have the old light on pass side), I've only cut the wires on the drivers side. Any help, thanks


    Oh ya, this is a older unimount, 7.6
     
    Last edited: Nov 23, 2011
  2. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    Where did you cut the old harness? Near the plug? There is a wire, on many systems, that goes out from the truck and then loops rite back in again and then goes to ground to complete the curcuit that activates the plow lights. Sounds to me like you may have cut that wire. The signals, and markers, are connected in parallel so there is no switching involved; but the headlights are switched either by the relays or by isolation module, depending on the age of your system. In either case it sounds to me like you have broken that wire somehow and now the truck doesn't know that the plow is there so the plow will not light up. What kind of wiring do you have? Three plugs at the grill or two? Relays or isolation module? What model plow do you have? I can tell you the colour of the wire if you can provide those details.
     
  3. wls

    wls Senior Member
    Messages: 319

    I cut the harness out by the headlight, was just going to cut/splice the new wiring into it. I think I may have fried something, had the ground hooked up wrong, the brown w/orange stripe, I belive is the ground. The white on the new headlight is ground, without thinking I hooked white to white, so Could I have fried a relay? Its a older plow, probably 80's 90's, has 2 relays. 2 plugs at the grill. The truck side wiring is about 3-4 years. Thanks
     
  4. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    If you mixed up some wires you could well have fried a relay. Check your fuses and the relays but be sure you have the wires right before turning things on again.
     
  5. wls

    wls Senior Member
    Messages: 319


    relays I know where there at, 2 of them by the drivers side battery, are there any fuses in the western harness, I did'nt put it in, and the truck fuses, I see a 30 or 40 amp fuse in the fuse box under the hood.
     
  6. wls

    wls Senior Member
    Messages: 319

    went to my son-in-laws today, put 2 new relays and hooked up to his plow, still no headlights, only the blinkers work, got home pulled the wiring harness, and relays up out of the cavity it was stuffed down in, and saw a brown wire with a male end on it, loose, there are 2 brown wires that come from the truck side plug towards the relays, one goes to the relays, the other I think goes to the park lights, thus the reason for no park lights, so does the brownwire, complete the circut, maybe being unhooked reason for no headlights??
     
  7. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Without park input from the brown wire the headlamps won't switch to the plow. That is the wire that handles the switchover. Thumbs Up
     
  8. wls

    wls Senior Member
    Messages: 319

    yep tore out the headlight assembly, saw where the wire went everything works now, thanks everyone.
     
  9. DJC

    DJC Senior Member
    Messages: 481

    Good job WLS!!!