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unimount wiring ?

Discussion in 'Western Plows Discussion' started by wishingtoplow, Mar 7, 2011.

  1. wishingtoplow

    wishingtoplow Member
    from Pa
    Messages: 86

    Got a good one here for you guys. While plowing i lost my parking lights on truck and plow and my headlights switched from plow to truck. With the plow unplugged i still have no parking lights on truck. turn signals on plow are also inop. I have power at parking light fuse in fusebox. i hooked test light up to power and touched it to my black/yellow parking light wire and it light up signifying it is somehow grounded. I am sure this is related to my plow wiring somewhere. Where do i start?
     
  2. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    Sounds to me like you are just not getting power to the park lights on the truck. When you put the test light on Pos and then to that wire it found a ground through the lamp fillament to ground, that is normal but the test lamp might have been a bit dimmer than with full power. I don't know what model of plow you have so I don't know the exact circuit but I can tell you that the plow park lamps and the vehicle lamps are connected in parallel. They should both be on at the same time. I would be looking at the headlamp switch on the truck. The fuse makes power available to the headlamp switch but if the switch is faulty it won't pass that power forward. If there was a short to ground on the park lamp positive feed wire then the fuse would have blown. What kind of plow and truck do you have? More detail in your description will allow for better responses.
     
  3. Western1

    Western1 Senior Member
    from MI.
    Messages: 679

    Sounds like a relay wiring system. The headlight relays require power from the running lights to switch the truck headlights over to the plow headlights. So when you lost the running lights on the truck that caused the plow lights to switch back to the truck lights and of course no running lights on truck or plow. As for whats wrong you should check where the headlight relays are for broken wires or corrosion. They should be found behind the driverside headlight.
     
  4. wishingtoplow

    wishingtoplow Member
    from Pa
    Messages: 86

    is there anyway to test the relays?
     
  5. Western1

    Western1 Senior Member
    from MI.
    Messages: 679

    You can put power to the terminal where the brown wire is connected to see if the plow lights come on. Check the brights. Both relays don't usually go bad at same time.
     
  6. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    You still have a problem with the vehicle's park lamp power. The relays rely on that power so if the park lamps are dead the relays are inactive. The relays don't have anything to do with this problem in my opinion. Get the park lights working and the plow lights will come back.

    Just take a jumper wire from battery + (preferably a jumper with a fuse) and connect it to the park lamp + wire just before the blulb. Since all the park lamps are in parallel all of them should come on if I am correct. The plow lights will also work because they are tied into that same circuit. If that works then you have either a broken wire between the lamps and the light switch or a bad light switch.
     
    Last edited: Mar 7, 2011
  7. twinman326

    twinman326 PlowSite.com Addict
    Messages: 1,683

    Check the brown wire the comes off the parking lamp (driver side) and see if it is grounding (touching metal). This is the wire that activates the relays to switch from truck to plow..

    If the wire is ground out somewhere this might also create problems with the truck itself being that it is connected to the main harness..
     
  8. wishingtoplow

    wishingtoplow Member
    from Pa
    Messages: 86

    so, i hooked a positive wire from the battery to the parking lamp and waalah! parking lights. Does anyone know what color wire goes to the headlamp switch. there are two sockets. two wires coming from that are black/orange and yellow/black. black is a good ground. I assume this is the wire that sends power to the parking lamps. I have no power coming out of there. Can someone explain where the power goes to after it leaves the fuse box
     
  9. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    Unfortunately we / I don't have access to specific vehicle wiring schematics, only the plow systems. You could try Mitchell Online, I think you can pay for a week's access to all their tech info online. When I worked at an auto mechanic that's what I used but we had a subcription. You could consider buying a Haynes book at your local book store. You know you could just install a temporary switch from a hot source (with an inline fuse) through a simple switch to that point you jumped to. That way you just turn your park light on manually until you get a vehicle schematic.
     
  10. wishingtoplow

    wishingtoplow Member
    from Pa
    Messages: 86

    one step ahead of you buddy ;) already done.