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Light Problem

Discussion in 'Fisher Engineering Discussion' started by JBano13, Dec 22, 2009.

  1. JBano13

    JBano13 Member
    Messages: 39

    I have a gmt-900 with a mm2 RD and my low beams on the plow won't go on. The parking lights, turn signals work, and high beams work but the low beams won't switch over from the truck.
     
  2. RepoMan207

    RepoMan207 PlowSite Fanatic
    from Maine
    Messages: 5,031

    Allow me to think out load and to get some more information....

    Who did the install?

    3 or 4 port?

    Did you reverse the 4 reversible 2-position connectors (although I think that would only apply to one light being out)?

    Have you checked or replaced the bulbs? If you even have one bad bulb, it can make for harder diagnosing.

    How old is the plow? Which style lights does it have?
     
  3. JBano13

    JBano13 Member
    Messages: 39

    Plow is 2 years old, bulbs are good, the fisher dealer did the install, it has the new style headlights, and I'm not sure whether it is 3 port or 4 port. They worked when it was installed but then I had work done to my truck and they must have touch something they weren't suppose too and screwed up my lights.
     
  4. RepoMan207

    RepoMan207 PlowSite Fanatic
    from Maine
    Messages: 5,031

    Go back and make sure that all four connectors are connected at the headlamps. The two gray ones to be specific. The black ones are for High beam if I remember right. They may have disconnected the Fisher harness and plugged the factory ones back in....Not likely, but it would be the first thing I would check on.
     
  5. JBano13

    JBano13 Member
    Messages: 39

    Will do, thanks!
     
  6. RepoMan207

    RepoMan207 PlowSite Fanatic
    from Maine
    Messages: 5,031

    One more thing to check it the two fuses that go to that harness....disregard, those are for the park & turn signals. sorry.
     
    Last edited: Dec 22, 2009
  7. JBano13

    JBano13 Member
    Messages: 39

    Ok, I'll check this out tomorrow hopefully, unfortunately to get to my isolation module and the back of my headlights I have to take off the grill of the truck.
     
  8. RepoMan207

    RepoMan207 PlowSite Fanatic
    from Maine
    Messages: 5,031

    Not sure how those headlamps are setup, but if there like the old ones you should be able to get at them by removing the headlamps. In either case it should be the same procedure as replacing a bulb.....
     
  9. JBano13

    JBano13 Member
    Messages: 39

    Dumb question, do you mean on the truck or plow?
     
  10. JBano13

    JBano13 Member
    Messages: 39

    I have my truck apart right now, I checked and all the fuses are good and I don't see any loose connections. I have been just tinlering around with everything for about an hour with no luck. The high beams, parking lights and turn signals all work flawlessly but the lows just won't switch over from the truck to the plow. Anyone have any thoughts of things I can try out or check while I have everything apart? And its a 3 port module by the way.
     
  11. RepoMan207

    RepoMan207 PlowSite Fanatic
    from Maine
    Messages: 5,031

    Yes, I meant the truck.

    So to clarify, the low beams stay lite on the truck even though the plow is plugged in. It's not just a matter of the plow low beams not coming on correct?
     
  12. JBano13

    JBano13 Member
    Messages: 39

    correct, the truck lows stay on and don't come on the plow but the parking lights are on the plow.
     
  13. RepoMan207

    RepoMan207 PlowSite Fanatic
    from Maine
    Messages: 5,031

    hmmm, I think the module may be junk then.
     
  14. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    How good are you with a test light and a wiring schematic? You need to check right at the Iso for power and ground coming in from the truck lights as well as power out of the Iso to the plow lamps.

    Rather odd to lose both sides though, as they're separate all the way through.

    3 port.jpg
     
  15. JBano13

    JBano13 Member
    Messages: 39

    I ended up just unplugging all my connectors at the headlights including my hid kit and then put it all bag together and now it works. Thanks for all your help!
     
  16. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    If thats all you did the issue may pop again so be ready but hopefully you get lucky and its never a problem again. Good luck. :drinkup:
     
  17. JBano13

    JBano13 Member
    Messages: 39

    I'm guessing that something was reversed or some connections were mixed up and just didn't notice it and corrected it by starting from scratch, so hopefully it wont happen again.