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Unimount MVP Control Problem

Discussion in 'Western Plows Discussion' started by bigmackmiller, Jan 29, 2014.

  1. bigmackmiller

    bigmackmiller Member
    Messages: 32

    Hey guys I have an older Unimount MVP mounted to a 2001 GMC 2500HD, I am having problems with the control constantly turning on and off or just shutting off all together, especially when trying to make the plow perform different actions, have checked connections and still seem to have the problem any ideas where else I should look? Also wanted to add it is the two plug harness, and plow headlights are bypassed and wired direct to a toggle
     
    Last edited: Jan 29, 2014
  2. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    If u have a two plug the headlights don't need to be connected for the controller to work. Check the ignition feed wire. Check the grill plugs and make sure your fuses r seated well.
     
  3. bigmackmiller

    bigmackmiller Member
    Messages: 32

    Ok thanks I will check the plugs when I get home, know the ignition wire is good I checked that last night. I'll report back after I check the plugs
     
  4. firefighter1406

    firefighter1406 Senior Member
    Messages: 328

    Check for crushed wires in the loom. I had a similar issue this week but mine would pop the fuse for the controller. I had some wires that had gotten smashed and was causing an issue.
     
  5. bigmackmiller

    bigmackmiller Member
    Messages: 32

    Ill check the wires in the loom tomorrow in the day light, tried the grill plugs but got the same result, if a video might help I can make one to show whats going on
     
    Last edited: Jan 29, 2014
  6. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    When the controller "shuts off" does the back light go out or does the power light go off so u have to turn it back on again all the time? And when it does fail what do You have to do to re-activate it? Either way it is electrical. There are only three main components involved. The controller (and cable), the control harness from cab to grill and the light / control cable on the plow. Of course u need to check all the fuses and connections like I said earlier. Fuses, battery connections, motor relay connections and the grill plugs. You need to get a copy of the schematic for the uni MVP and start testing when it fails. I can't link u to it from my iPhone but when I am at a computer I will link u if no one beats me to it.
     
    Last edited: Jan 30, 2014
  7. bigmackmiller

    bigmackmiller Member
    Messages: 32

    Last edited: Jan 31, 2014
  8. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    assuming this is a nine pin relay system have a look at this link on page 54 http://library.westernplows.com/ddcommon/dd_pdf/pdfs/22373.07_110108_for_web.pdf
    Find the pump motor and the three valve coils.... Notice that they all connect to a common negative. At the top of the three coils notice that the Blk/Org wire (negative) goes back to pin 5 of the grill plug. This wire, I believe, connecting to ground is what activates the controller. But the diagram doesn't show how the relays are involved. I would try finding that Blk/Org wire on the truck side and jump it to ground. Plow on or off this should activate the controller backlight. Also look on the motor relay. There you will see the ground symbol coming off the relay coil, on the left of relay, with yet another Blk/Org wire. This is how that circuit we talked about finds it's way to ground at the battery. Look there too and make sure that wire is in good shape especially where it connects to the relay, relay bolt to fender or battery negative post. It may be at any of these location because electrically it's the same. Bare with me on this, these older relay systems are not my strength, if I am leading him in the wrong direction somebody speak up....
     
  9. bigmackmiller

    bigmackmiller Member
    Messages: 32

    Ok did some checking last night, it decided to rain instead of snow, think I'd rather have the snow, anyway was checking all the wires in the harness under the good, tried grounding the black and orange to the neg. on the batt. Didn't change, I then stretched the control out the window so I could mess with the harness while I was moving the plow, and it did not miss a beat went through all the movements. I then sat back in the truck to see if it would act up again and sure enough it started shutting off again. So I'm about 90% sure that I've isolated the problem within the wires that run out of the controller to where they connect to run to the truck side harness. Is it possible to replace that section or do you have to get a new control?
     
  10. Whiffyspark

    Whiffyspark 2000 Club Member
    from SOMD
    Messages: 2,402

    Is this round 10 pin?
     
  11. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    U can get cables and circuit boards for controllers individually, yes.
     
  12. bigmackmiller

    bigmackmiller Member
    Messages: 32

    Yes round 10 pin
     
  13. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    Now u need to figure out which half of the plug is the problem. The truck side or controller side.
     
  14. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    Have a look at this link http://library.westernplows.com/westernplows/pdffiles/29013.04_110109_for_Web.pdf
    Under the controls section item 51 is the controller harness, just select the correct version from the table. There are several different types with different numbers of buttons. 64 gives you a new molex connector and wire removal tool but not the wire ends you click into the molex connector. 66 will give you a bag of ten truck side controller harness ends to push into the molex connector. 70 is what they call a molex repair end. Not sure as I have never ordered one of these but it looks like a few inches of wire with the ends already attached. This would be nice as you just have to cut off the old ends and butt connect & heat shrink the wires color to color.

    If you have a good close look at the molex plug and play with the individual wires on the truck side of the plug you should be able to figure out what you need.
     
  15. Whiffyspark

    Whiffyspark 2000 Club Member
    from SOMD
    Messages: 2,402

    Yeah he might even have a pin pushed back a little. Or a broken pin.

    If you buy the repair cut they have a tool that allows you to remove the pins
     
  16. bigmackmiller

    bigmackmiller Member
    Messages: 32

    Ended up just replacing the control and it runs like a champ now not cheap but happy its working and like the newer style control much better, thanks for all your help getting this sorted