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MM Won't angle or drop

Discussion in 'Residential Snow Removal' started by pamante, Jan 20, 2016.

  1. pamante

    pamante Junior Member
    Messages: 13

    New poster
    Just bought a 1998 Jeep Sahara with an older Fisher MM plow - plow was clearly not maintained well.

    I used it once - the next time it snowed the plow wouldn't angle or drop.

    Checked and cleaned the connections through the grill

    Replaced all the spade connections on the solenoids. The wiring diagram on line is a little different than the Jeep. One of the solenoids looks backwards.

    I can hear the motor run but blade won't move right left or drop

    Replaced the fish stick with an aftermarket one.

    Big storm coming - help please
     
  2. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,971

    How many plugs at the grill?
     
  3. pamante

    pamante Junior Member
    Messages: 13

    Thanks for the response

    Two plugs at the grill
    One for power
    The other had lots of pins. There were not the same size pins though. I thought the female part of the connector may have broken off and stayed on the male side - but it doesn't look like it.
    Should they all be hte same size
     
  4. Randall Ave

    Randall Ave PlowSite.com Addict
    Messages: 1,982

    You did check fluid level? Does the motor sound like it is struggling, or free wheeling?
     
  5. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,971

    Double check the blk/org at the coils. That's the ground. It comes off the plow motor, that's the small wire off the main ground.
     
  6. pamante

    pamante Junior Member
    Messages: 13

    Thanks for the replies

    I actually replaced the ground. It was questionable at best.

    It looks like one terminal on every solenoid is connected via black/red wire. I would thing the would all be the same location, back. The S2 ground is on the front terminal. Is that correct?

    The motor sounds fine. I can't really tell if there is enough fluid with the lift piston stuck in the up position. From what I can see, it looks foamy like there is air or water in it. Is it just AT fluid?

    Paul
     
  7. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,971

    The 3 coils get there ground from that motor stud up front. Blk/org and are all connected together.
    What you could do is run a jumper wire from your trucks ground to the motor just to make sure
    Then your gunna need to see if your getting power to the coils when you operate the controller
     
  8. pamante

    pamante Junior Member
    Messages: 13

    I'll give it a try at lunch

    Should I bypass the wiring harness and link the grounds directly to the stud?

    Should all the grounds be on the same side of the solenoids? They aren't. Not sure it matters with a solenoid though.

    Is the fluid just ATF fluid?

    Thanks
    Paul
     
  9. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,971

    Can try going from the motor stud to one of the coils, or straight from your trucks battery.
    Atf is ok.
     
  10. pamante

    pamante Junior Member
    Messages: 13

    I checked all the connections I could. I pulled the solenoids and the valve bodies. The S3 (longest) had some bad o-rings. Replaced the whole thing. ($74)

    The solenoid on S1 went on hard. The shaft of the valve body seemed swollen at the end. But plow goes up when I push the button - just won't come down or angle.

    I drained all the fluid. Very light pink - water and air in it. Could this bad fluid or air in the system be the cause?

    It's a yard truck so it isn't registered and can't be driven it to someone to fix it.

    Anything I haven't tried?
     
  11. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,971

    Pink is usually water. Did you also flush out the rams?
    If the coil was hard going over the valve, usually indicates a bad valve.
     
    Last edited: Jan 21, 2016
  12. pamante

    pamante Junior Member
    Messages: 13

    I drained all the fluid. I'm waiting for a valve cartridge to come in. When I took the coils off the first cartridge it was tight. The cartridge itself looked swollen. Should be here tomorrow. I'll give it a try then.
     
  13. pamante

    pamante Junior Member
    Messages: 13

    OK - I'm at a loss. I replaced all three valve cartridges with aftermarket SAM units. I also replaced the hand held controller unit from SAM as well. I drained the fluid. It was REALLy bad - lots of water. Replaced all the spade connectors. When I try to angle it, it moves slightly then stops. Still won't go down or float. After I replaced the last valve - it angled back and forth ONCE. I'm thinking it could be air bound.
     
  14. Randall Ave

    Randall Ave PlowSite.com Addict
    Messages: 1,982

    You cleaned or replaced the filter, and cleaned out the resivior housing? Removed hoses and flushed out the rams
     
  15. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,971

    While in float, did you test light the coil to see if your getting power to it?
     
  16. pamante

    pamante Junior Member
    Messages: 13

    Yes. Driver side coil has power in float
    Fault light is intermittent on the controller
    Now nothing. No motor spin
     
  17. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,971

    So you have power at s1/wht/yellow when you go in float and it doesn't lower?

    Did you mess with the quill at all?
    And you said you inspected the s1 valve itself?
    Did you try to hotwire the coil itself, power and ground? Can also try loosening the lift ram nut, might be rusted and putting the lift cylinder in a bind

    Double check where you have the controller powered up at. Wiggle the wire and see if that works.
     
    Last edited: Jan 31, 2016
  18. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,971

  19. pamante

    pamante Junior Member
    Messages: 13

    Correct. S1power and magnetized
    What is the quill?
    No to the hot wire coil. Will try that now
     
  20. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,971

    Did you try to add a ground wire directly to the coils bypassing the factory wire