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Truck lights don't work properly with plow off?

Discussion in 'Western Plows Discussion' started by shannon2537, Nov 30, 2013.

  1. shannon2537

    shannon2537 Junior Member
    from Iowa
    Messages: 4

    This is my first Thread wish me luck!
    One of my trucks is a 1985 K20 quad headlight with Ultra MVP Plus w/ 3port Isolator, everything seams to work properly with plow on but with the plow off only the upper headlights work on high and low beam and the lower headlights only come on very dim, anybody have any ideas? I have checked grounds and cleaned all terminals and dielectric greased them. When I unhook the Isolator and reconnect the factory wiring the headlights work perfectly.
     
  2. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,970

    Try flipping the plow to tk headlight connector 180 degrees. From A to B
     
  3. shannon2537

    shannon2537 Junior Member
    from Iowa
    Messages: 4

    The connecter is a 3 prong can't be flipped but I did switch the low beam and common on one side and that has made a difference. Now it appears to work but the pass side seems to be a bit dimmer than the drivers side, now to put the bats. back in button up and put plow on and see if plow lights work properly.
    Thanks for the suggestion, I will post the final results later today.
     
  4. nealybird

    nealybird Senior Member
    Messages: 715

    hi Shannon,
    welcome to the forum! if you don't get it by Monday, Doug can help you through it. thanks!
     
  5. Whiffyspark

    Whiffyspark 2000 Club Member
    from SOMD
    Messages: 2,402

    Dim lights are usually a ground problem
     
  6. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,970

    the gnd is the center pin per westerns diag
     
  7. shannon2537

    shannon2537 Junior Member
    from Iowa
    Messages: 4

    Ok so I traced all truck side feeds and matched them to the correct input feeds into the isolator and then back out to the lights. Just had to wrap my mind around the way the isolator operates.... Then it was pretty straight forward.
    Thanks to all for the suggestions.
     
  8. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,970

    So what was it?
     
  9. shannon2537

    shannon2537 Junior Member
    from Iowa
    Messages: 4

    Truck to Isolator, Literally had wires crossed and different from right to left so had power bleeding back through ground
    Don't know how they got that way!
     
    Last edited: Dec 2, 2013
  10. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,970

    Ok gotcha. Well its fixed now.