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Mvp plus pump running as soon as it hooked to truck

Discussion in 'Western Plows Discussion' started by Basilry, Jan 30, 2016.

  1. Basilry

    Basilry Junior Member
    Messages: 8

    I searched for a while and could not find anything. I have a 2006 Dodge Ram with a 2006 MVP plus 8.5 V plow. Have owned the plow and truck since new. Today I went out to hook up the plow to replace the lift ram because it has had a slow leak. And it's supposed to snow this week and I had time today to work on it. As soon as I connected the power cables up, the pump turned on but wasn't moving anything. No matter what I did the pump still ran with or without the truck running and with or without the key on. The power light on the controller is also flashing. I looked over all the wires and can't find anything obvious. I'm thinking its a stuck solenoid but could not figure it out and just got frustrated with it. And of course it's Saturday afternoon and no one with plow parts is open. Any suggestions?
     
  2. 1olddogtwo

    1olddogtwo PlowSite Fanatic
    Messages: 11,521

    Start with a fresh solenoid see if the problem still exists

    Also check ALL the grounds.
     
  3. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,963

    Yep........
     
  4. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    Flashing red light means communication problem. Motor solenoid staying on suggests plow module.
    I would disconnect one of the small wires on the solenoid before replacing it. If the motor stops spinning with the little wire off then I would focus on the plow module or damaged wires on the module harness under the black plastic shroud. Any chance you have mice nesting in your plow?
     
  5. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    Looking at the schematic I see that you could also test the solenoid by either pulling all four fuses from the plow harness (under the black plastic shroud, two fuses on each side) or by pulling the middle plug on the plow module. Either way will disconnect power from the coil of the solenoid. If the solenoid is physically stuck it will still spin the motor when you plug it in. If it's the plow module or associated wiring then it will not spin with one of these options applied. Since everything is closed today, why not do some "no parts required" testing first.....
    I also noticed on the schematic that the solenoid and two valves share a common positive. So.... if the black wire (ground side) on the solenoid is pinched somewhere or chewed by mice then it could be grounding out, This would cause the solenoid to close and the motor to spin. May be just a bare spot on that black wire touching metal somewhere inside the pump. That would be an easy fix...
     
    Last edited: Jan 31, 2016
  6. Basilry

    Basilry Junior Member
    Messages: 8

    Thanks guys I will try your suggestions and see what I can figure out. I know there is not a mouse nest under the cover I had that all apart yesterday and was cleaning wires and checking connections but everything was looking good. I will write back with what I find.
     
  7. Philbilly2

    Philbilly2 2000 Club Member
    Messages: 2,586

    OH BOY... the mice strike again...
     
  8. theguynextdoor

    theguynextdoor Senior Member
    Messages: 307

    I had this problem once. As soon as I plugged the plow wires into the truck wires, the pump would start running. If I remember right, it was because I had put one of the small wires on the wrong terminal when I installed a new solenoid.
     
  9. scottL

    scottL PlowSite.com Addict
    Messages: 1,600

    Module went bad or wires are shorted payup
     
  10. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    "I had this problem once. As soon as I plugged the plow wires into the truck wires, the pump would start running. If I remember right, it was because I had put one of the small wires on the wrong terminal when I installed a new solenoid."
    This is a multiplex unit with the solenoid on the plow. There are only two wires for the two small terminals. No matter how you hook it up it won't make the solenoid go on. This is a moot point.
     
  11. Philbilly2

    Philbilly2 2000 Club Member
    Messages: 2,586

    Saw that too, he must be talking on an older plow with the solenoid under the hood
     
  12. Basilry

    Basilry Junior Member
    Messages: 8

    Put on a new selenoid this morning and still had the same issue. Talked to my dealer and ended up putting a new plow module on. Thanks for all the help and suggestions.
     
  13. theguynextdoor

    theguynextdoor Senior Member
    Messages: 307



    Oops, I didn't realize he had a fleet flex plow. Forget what I said then. I was talking about a 3-plug pro plus with the solenoid under the hood.
     
  14. Basilry

    Basilry Junior Member
    Messages: 8

    So thought my plow problems were over but not so much. Plow worked this morning, it went up on the way to my shop and down when I got to the shop. Went out this evening and started the truck to let it warm up and grabbed the controller and nothing. No power at all. Wiggled the plugs but nothing. I have lights but no power to the plow. Checked the fuses on the top side of the plow and they were both blown. It has been raining all day which leads me to believe something got wet and shorted out? :mad:
     
  15. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    That sucks :realmad:

    There are four fuses on the plow, one pair on the right and another pair on the left. On the left (driver's side) one of those fuses feeds the motor relay (solenoid) and the plow module. I don't believe that the rain should cause fuses to blow, rain is soft water and a poor conductor. You can put two wires directly into a bowl of fresh water only an inch apart and connect them to a fully charged 12V battery, there will only be milliamps of current. Not enough to blow a ten amp fuse for sure.

    I wonder, did you change your plow module yourself or did your Western dealer do it? Is it possible that a wire got pinched under the module. Sometimes when a wire gets pinched it takes a while before the insulation breaks and the short occurs.

    Put new fuses in and pull the wires out a bit under and behind the shrouds. Look close at where they run and ensure they are not pinched anywhere.

    On second thought..... you said the controller didn't light up right...... If the plow module is getting no power then your controller would still light up but you would get a flashing red light indicating communication failure. This may well be an altogether new problem.

    Check the two fuses by the isolation module under the hood too.
     
    Last edited: Feb 2, 2016
  16. Basilry

    Basilry Junior Member
    Messages: 8

    I looked at the fuses on the right side and they were blown. It was raining out and I was already late so I just chained it up and ran home. I will look at it more tomorrow when I can pull it inside out of the rain. I will check over all the wires and see what I can find before I put new fuses in. I just wish wish western would have used a more common fuse instead of a 4 amp.
     
  17. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    You could use 5 amp fuses. It's not the end of the world....
     
  18. Basilry

    Basilry Junior Member
    Messages: 8

    Had some time today and cleaned and checked every wire on the plow today and reinstalled with dielectric grease. Also changed 3 of the 4 fuses on the plow that were blown. Both on the passenger side of the plow were blown and one of the two on the driver side were blown. Hooked the plow back up and I'm back to the original problem where the pump turns on right away. I put the old selenoid back on to see if that made any change and no change. I rechecked all the wires and everything looks like it should. I'm actually surprised at how clean everything is under the plastic covers on the plow. I will investigate more tomorrow but I'm getting to the point where I'll let the dealer deal with it. :realmad:
     
  19. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    Looking at the fuses that were blown I see that they have a common positive, through the respective fuses, then they go through the valve solenoid coils and on to ground through the plow module. I guess my point is that the only thing that would blow one of those three fuses you speak of would be either a shorted coil or a pinched wire between the fuse and the coil. But.... it is not likely that there would be three shorted coils??? I think you have pinched wires. I would pull the plugs from port B and C on the plow module and then pull that short harness right out of the plow. This harness goes from the module plugs to the valve coil solenoids so you would need to pull the wires off the coils too. Pull that harness right out and look for damage to the wires. I think that you will find you can't pull them out because they are under pinched under the plow module or something. Or perhaps they were damaged by some sort of strike that pinched them between the plastic shroud and the valve body housing. In any case to blow those three fuses three of those wires must be damaged and shorting out either continuously or intermittently.

    When plug B is disconnected you will find that you also need to disconnect the two small wires from the solenoid after which the solenoid cannot possibly be activated, so.... if you connect the grill plugs, turn on the ignition and activate the controller the pump motor will not and cannot spin up unless the solenoid is stuck in the on position in which case the solenoid, new or not, is no good.
     
  20. Basilry

    Basilry Junior Member
    Messages: 8

    I went into the shop this morning and looked over everything. Checked every wire and connection looking for any signs of breakage or corrosion or a pinch. Nothing at all. So the plow is hanging on the truck and going to be dropped off tomorrow morning for the dealer to figure it out. Ill keep you posted.