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Plow headlights, one out

Discussion in 'Western Plows Discussion' started by hopsing415, Dec 13, 2015.

  1. hopsing415

    hopsing415 Junior Member
    Messages: 17

    Hi all, I have a 3 plug system with a 4 port isolation module and have 2 headlights out at all times. Low and high beams both have the drivers plow light and passenger jeep light out.I was told is was the ground wire on the plow drivers side so I checked the wire and have continuity from light to module. Have any of you had this problem and if so what am I missing? Thanks for help in advance.
    Patrick
     
  2. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,946

    Ok, more info.
    What truck is this on?
    And specifically what light is out and what lights are on?
     
  3. hopsing415

    hopsing415 Junior Member
    Messages: 17

    '04 Liberty. drivers plow and jeep passenger headlights out, high and low beam.
     
  4. hopsing415

    hopsing415 Junior Member
    Messages: 17

    all other light work
     
  5. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,946

  6. hopsing415

    hopsing415 Junior Member
    Messages: 17

    All fuses are good. Been on the Jeep since the plow was new, 5 years ago.
     
  7. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,946

    What i would do, start by test lighting the headlight connectors and see what your missing, power or ground, then start moving to other connectors and do the same.
    Anything done to the truck lately?
     
  8. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    Perhaps try isolating the problem between the jeep and the isolation module wireing by unplugging the Western harness and plug the OEM wires back on the headlight bulbs. If the Jeep lights work then you know it's in the plow system but if not then fix the Jeep issues first. The isolation module requires reliable signals from the vehicle to work properly. If the jeep lights work then I would swap in an isolation module, if you can borrow one for testing. If you don't have access to a module then you will have to do as dieselss says and trace the wires one by one...... But take my advice and don't poke the wires with a probe or the little holes will cause more problems down the road.
     
  9. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,946

    But take my advice and don't poke the wires with a probe or the little holes will cause more problems down the road.

    Yes. Exactly. Never poke the insulation. Good point Nick.
     
  10. hopsing415

    hopsing415 Junior Member
    Messages: 17

    Great advice, thank you both. Done for the day today, no snow in the near future here in the Boston area so I have time. Thank you and will be back.
    Patrick
     
  11. hopsing415

    hopsing415 Junior Member
    Messages: 17

    the jeep lights work when they are not plugged in, still think I need to isolate from the module? I will give that a try when out of work today or tomorrow but was thinking if it would make a difference since the problem only occurs when I have the 11 pin plugged in
     
  12. Philbilly2

    Philbilly2 2000 Club Member
    Messages: 2,552

    Sounds like a unique problem here.



    Any chance for any reason the iso module got unplugged and re connected at any point to do some type of service or maintenance on the jeep since last hook up?
     
  13. hopsing415

    hopsing415 Junior Member
    Messages: 17

    Iso module not disconnected at any time. This is fun huh?
     
  14. Philbilly2

    Philbilly2 2000 Club Member
    Messages: 2,552

    What do you mean by fun?
     
  15. Philbilly2

    Philbilly2 2000 Club Member
    Messages: 2,552

    I have to ask... is the drivers plow headlight bulb good?

    If you are able to check continuity, I am assuming you already checked that, but I just have to ask.

    Can you also walk me threw the headlight changeover? I have read your post at least 20 times and I am still not clear:

    EX:
    Plow unhooked - Both Jeep headlights work properly

    Plow connected low beams - Plow lights on - passenger plow on drivers plow out

    Plow connected high beams - you know the drill
     
  16. hopsing415

    hopsing415 Junior Member
    Messages: 17

    I am a happy guy, by fun i mean it's fun and challenging at the same time. All bulbs are good, can switch them around.

    Plow unhooked - Both Jeep headlights work properly

    Plow connected both low and high beam - Plow lights passenger on, drivers out
    Jeep lights passenger out, drivers on
     
  17. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    This is either the isolation module or the wiring from port 2 and the headlights on the plow. Pull the wire out of your grill and have a good close look for any damage inch by inch. Look close at the pins in the grill plugs. If no damage is found then plug that cable back into the 11 pin headlight plug on the plow and check for continuity from the plug that came out of port two of the isolation module to the headlight plugs inside the plow headlight housing. The possible causes are: damaged wires, bad broken or corroded pins in the 11 pin plug or a bad isolation module.

    It's time to either get out the multi-meter or start buying / borrowing parts to substitute in as a process of elimination.
     
  18. hopsing415

    hopsing415 Junior Member
    Messages: 17

    Thanks Mishnick. I will let you know when I pin out port 2 to the headlight housing.
     
  19. hopsing415

    hopsing415 Junior Member
    Messages: 17

    Port 2 to the lights all pin out good, continuity on everything I need. Module is bad? what are the chances of a module going bad?
     
  20. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    It is mostly relays inside so they do go bad.