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MM1 Light Issues

Discussion in 'Fisher Engineering Discussion' started by SIWEL, Dec 5, 2010.

  1. SIWEL

    SIWEL Senior Member
    Messages: 129

    I have a 1995 Ford with a Fisher MM1 relay control 2 plug plow. It is a 9 Pin plug. I did the install with one of my guys and I hooked up the plow. I have checked and re checked the relay's and the way the wires are hooked into them, and they seem to be correct according to the wiring diagram.

    The problem is I only have plow headlights now that I have wired the truck. All the running lamps stay lit, but only have plow headlights. I know you are supposed to only have plow lights with the plow plugged in, but the truck headlights do not come on when you unplug the plow.

    I have been trying to trace the problem, and I think it could be caused by the relay, I do not know how to test them or if it is possible. All the wires seem to be intact and functioning as they should be (as far as I can figure out).

    Question 2 is a bit more breif. Sometimes when using the functions on the plow, the pump stays ingauged, but no functions are happening. Could this be a sticking relay on the plow pump?


    Any help would be greatly appreciated, its suppsoed to snow soon.

    Thank you for your help,
    Ryan
     
  2. Mnpowerstroke99

    Mnpowerstroke99 Member
    Messages: 82

    I'd try a new relay.Did you try high beams,there is a relay for each high and low beam?
     
  3. SIWEL

    SIWEL Senior Member
    Messages: 129

    replaced the relays and nothing changed. HELP!
     
  4. SIWEL

    SIWEL Senior Member
    Messages: 129

    Anyone know what my issue could be?
     
  5. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Remove the black/orange wire from both the relays. Do the truck side light now illuminate? If so then the relays are being grounded all the time (even with the plow disconnected) which they shouldn't. So it's either wired incorrectly or the black/orange is grounded out on the truck side somewhere, which also may fall under the incorrectly wired category.


    Question #2: Change the under hood plow solenoid before it stick on and burns it and/or the cables up.
     
  6. SIWEL

    SIWEL Senior Member
    Messages: 129

    plow solenoid is changed. Will try the black/orange wires today and see what happens. thanks
     
  7. SIWEL

    SIWEL Senior Member
    Messages: 129

    ok, so if I disconnect the black and orange wire, the headlights come on on the truck. If I plug them in the headlights go to the plow only. So, I must have a bad ground... somewhere?
     
  8. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    If you check the black/orange with a test light you'll find it has ground whether the plow is plugged in or not, which isn't correct and is the reason the lights don't switch back to the truck. So either it's shorted to ground, or you have it wired incorrectly. Time to double check.