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Fisher mm2 motor stays running

Discussion in 'Truck & Equipment Repair' started by stacks04, Feb 3, 2015.

  1. stacks04

    stacks04 Senior Member
    from ct
    Messages: 119

    Hey all, need some assistance figuring out an issue I'm having. This past Monday night, my plow after a long day of use started going up very slow. It would temp correct itself if i let it sit idle for a while. But would quickly act up again. I thought it was a solenoid issue at first because one of the terminals was melted. After using it for 20 minutes or so it started moving very slow. Ended up replacing the motor today on the advise of my local dealer. Still would go very slow after some plowing. They recommended changing the fluid and filter just in case it had moisture/ice in it thus clogging the filter causing the slow movement. After i reinstalled the pan and fluid the plow now doesn't shut off. I have to unplug the power plug at the grill to shut it off.
    I tested the control, and control signal and they go off as soon as the button is let go. Tested the ground side of the solenoid and is ok. Checked wiring and swapped battery harness with known good one and still stays running. Got another new solenoid and it does the same thing with the new solenoid as well.
    If the battery connector is not connected to the plow the solenoid clicks on and off as it is designed to. It only stays stuck on when connected to the motor.
    Any thoughts would be helpful. I'm fried trying to fix this thing all day. As we're fixing to get more snow in the next day or so.
  2. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,391

    If this all started after you replaced the motor, look at your connections.
    Also remove the pos cable at the motor, and then do all your electrical test.
  3. stacks04

    stacks04 Senior Member
    from ct
    Messages: 119

    I will head out in a little bit too do that. I'll report back what i find.