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MM1 Help Please

Discussion in 'Truck & Equipment Repair' started by mayhem, Dec 11, 2010.

  1. mayhem

    mayhem PlowSite.com Addict
    from Peru MA
    Messages: 1,016

    Background:

    Coulpe years ago one of my truckside wires frayed and the blue wire broke on the directional control cable (the three wire plug in a three wire MM1 setup). Ran a jumper wire to bypass the problem and proceeded to ignore the issue for a couple years.

    Fast forward to today:

    Installed the replacement plug end (note, splice in plug end, not a whole new end to end cable). Removed my jumper wire and hooked everything up...plow now only goes to the right. Up and left run the motor, but the plow doesn't move. I checked the wiring as best I can and it seems correct, but obviously there must be a problem...a couple weeks ago I used the plow successfully with the old plug and jumper wire. Logically the problem MUST be with my splices, right? Is there a continuity or voltage test I can perform on the truckside plug to see if thats where I messed up? I hate to rip it apart only to find out the problem is somethign else.

    Thanks.
     
  2. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    The S3 valve is needed for angle left and raise...which is triggered by the blue wire. You can check the S3 for magnetism but I can pretty much assure you there won't be any, because there's no continuity on the blue wire.

    You know what comes next. :D
     
  3. mayhem

    mayhem PlowSite.com Addict
    from Peru MA
    Messages: 1,016

    Yes I do...and now its raining of course.

    Should I be able to see 12v from the blue wire to the battery ground when I hit the lift button and the plug is unplugged or does it need the S3 plug to be connected in order for the controller to turn on? If I can activate the controller then I can figure out where I'm losing voltage.

    I strongly suspect that when I spliced in the truck wires to the repair end that I may have let the truck side slip too far into the crimp barrel connector and I bet I crimped wire insulation and not copper.
     
  4. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Check the coil for mag first, even though I doubt you'll have it.

    Then disconnect the grill plug apply a 5 amp fused jumper wire to the truck side of the controller plug (disconnect the controller) in the cab and simply chase it with a test light out to the grill connector. Then plug the plow back in and check the plow side control harness too.

    Using the jumper makes it easy, no helper and no ground jumpers needed.
     
  5. mayhem

    mayhem PlowSite.com Addict
    from Peru MA
    Messages: 1,016

    I discovered yesterday afternoon that the plowside connector is bad...same wire that was bad on the truckside is frayed right at the connector on the plowside too.

    Thanks B&B for the help? Glad its a relatively simple fix. Of course both screws that hold to cover over the solenoids were rusted right in there and the heads sheared off them both, so now the cover is helpd on with some strips of velcro...but at least I know whats wrong and can go about getting a new plug on there before the snow flies.