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Fisher MM Headlights

Discussion in 'Fisher Engineering Discussion' started by DieselSlug, Nov 29, 2009.

  1. DieselSlug

    DieselSlug PlowSite.com Addict
    Messages: 1,054

    I ran into a problem mid season last year that i never fixed on the Fisher Minute Mount plow. The wiring is set up so when i plug the plow harness to the truck it switches all my lights right to the plow and off the truck. But when i a driving and i click the high beams they will come on on the truck, but not on the plow. All other lights on the truck Ex:parking remain off since they are on on the plow. Is it a bad relay that causes this?
     
  2. DieselSlug

    DieselSlug PlowSite.com Addict
    Messages: 1,054

    One other thing, does anyone have a wiring schematic for the light bulbs in the plow headlights, i had to splice these new wires in and the wires on the truck side are different than the plow side...
     
  3. buddymanzpop

    buddymanzpop Senior Member
    Messages: 601

    Do you have a two plug relay system or a three plug isolation module sytem? Wiring schematics are available on Fisher's website, www.fishersnowplows.com.
     
  4. DieselSlug

    DieselSlug PlowSite.com Addict
    Messages: 1,054

    I am really not sure, how can you tell? The plow is a 1994 Model Fisher MM
     
  5. buddymanzpop

    buddymanzpop Senior Member
    Messages: 601

    See if you have relays in your headlight wiring (5 spade, 12 volt relay, they are about 5 bucks a piece at Fleet Pride).
     
  6. buddymanzpop

    buddymanzpop Senior Member
    Messages: 601

    Are your connections good? no oxidation build up on pins or in holes on plugs, 94 will most likely have the relay system, the relay with a white wire as on of its wires will be the high beam relay the white wire is the high beam supply wire, put the high beams on and check that connection at the relay for power , if your test light lights up the problem is between the relay and the plow lamps.
     
  7. DieselSlug

    DieselSlug PlowSite.com Addict
    Messages: 1,054

    There are actually two relays behind my drivers side parking light, i believe one is for lowbeam and one is for high. So im guessing the relay is bad for the high beam? The connector where it connects to the grill is clean i keep it lubes up with anti corrosion grease.
     
  8. DieselSlug

    DieselSlug PlowSite.com Addict
    Messages: 1,054

    Ok sat dow the other night with a friend and he hlped me figure this wiring out. SO the relay was not clicking for the high beam as the low beam relay was, so i replaced it with a dodge 5 prong relay from a pickup. Fixed that, im also getting a weird connection issue with my low beams, that relay looks just about shot too, so today i went and grabbed about 10 more relays from dodges at the local junkyard, so that issue is fixed. On to the wiring, we figured most of it out till we got to the pass side turn signal wire. i am getting power to my plug at the grille but not to the headlight. So i checked continuity through the plow end of the connector, and it checked out good. So somewhere in the plow harness is a broken wire. So i am just going to run another wire right outside the sheath for now. I also am having grounding issues, my headlights are supposed to ground to the frame of the plow, and to the truck, they only have 4 wires coming out of them, but my truck harness has 5 wires going to each light. So i am guessing Fisher went to a little bit different style light at one point? So i am going to run run 2 grounds to the base of the lights on the plow frame. But it should work, we are going to get snow this weekend and the plow has to be ready before then....