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Truck won't shut off when MM2 lights are connected

Discussion in 'Truck & Equipment Repair' started by EddieChow, Jan 16, 2016.

  1. EddieChow

    EddieChow Junior Member
    Messages: 4

    Truck: 08 F350 Diesel with remote start (can find details on remote start if needed)
    Plow Fisher MM2, 3 plug set up, 3 port isolation module

    Problem:When the plow light plug is connected to the truck side plug, the truck continues to run when the ignition is shut off and key is removed. As soon as the plow light harness is unplugged the truck will shut off.

    It can not be shifted out of park (havent tried leaving it in any other gear)

    It seems like it must be demons in the ISO module and I have a spare Iso module that I plan to trouble shoot the problem with but wanted to get input on what the root cause of this kind of issue could be.

    Thanks to all in advance
  2. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,391

    Where is the plow controller power lead hooked up at?
    Might be back feeding the system. Try another location.
  3. EddieChow

    EddieChow Junior Member
    Messages: 4

    It's kind of jammed into an open space in the fuse block in the engine compartment. Which I think was a "repair" done by my mechanic when the plow wouldn't work after he replaced the oil pan.
  4. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,391

    Think you should start there?
  5. Randall Ave

    Randall Ave PlowSite Veteran
    Messages: 3,582

    There is s wire under the dash you can use for power supply. Used to be to right of column.