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VMD Problem

Discussion in 'SnowDogg Snow Plows' started by Ram 08, Nov 3, 2014.

  1. Ram 08

    Ram 08 Member
    Messages: 53

    So I got my VMD75 out yesterday to prepare for winter and I found a problem. The controller status light is blinking red 4 times. When I try to extend the left wing, the right one goes with into scoop position. They both move slower than normal while this is happening. Also if I try to angle the whole blade left I hear the motor/pump run but nothing happens. All other functions of the plow work normal.

    Looking online I find no service manual specifically for the VMD so I am looking at the service manuals for the VX plows assuming the electrical/hydraulic setups to be the same. (Scott M. or any other members please correct me if I am wrong on this).

    Based on everything I have read, I believe that I should be looking for an open circuit in the orange wire for S3A/B coils. Does anyone know if I am headed down the right path or if there is something else that would likely be the cause?

    Thank you in advance for any help.
  2. plowguy43

    plowguy43 PlowSite Fanatic
    Messages: 5,264

    Yes I think you are on the right track. If its just after storage, I'd check connections first. If that doesn't help then I'd go with a fluid replacement. If that doesn't work I'd go further into it - remove the cartridges and check for contamination.
  3. smoorman

    smoorman Sponsor
    Messages: 447

    Yes you are looking at the right stuff, and VMD is identical to VX/VXF hydraulics.

    If you have the light blinking four times, don't bother removing any valves. The blinking indicates an electrical issue. Also, with the way the VMD/VXF is wired, the controller only blinks if you've lost connection to BOTH S3A and S3B (ORANGE WIRE TO BOTH). This means the problem IS more likely in the grill connector or truck side harness. Check for voltage at S3A AND S3B, I'm guessing you won't have any. Check for broken or dirty pins.
  4. Ram 08

    Ram 08 Member
    Messages: 53

    Thanks Scott and Plowguy. I don't plow commercially so it sees very little use. The connector pins are like new and covered with dielectric grease. I will start checking the truck side harness when I get home. I am taking home my Maintenance man's tone generator to see if I can determine where a break might be. I have a suspicion that the harness is pinched too hard where it comes between the grill and bumper so I might have a broken wire.
  5. Ram 08

    Ram 08 Member
    Messages: 53

    After tracing everything out it appears my problem is in the connection between the plow and truck harness. I can manipulate/push/twist the connectors together and make the problem go away. The two halves of the connector are fully engaged. All of the connector pins are clean, dielectric greased, and look like new. I'm guessing possibly the male hollow pins have collapsed slightly and maybe the female side has opened slightly through wear/vibration?

    Scott - would it be possible to get the nominal ID of the male pins so I could have my Toolroom make a small tool that I would be able to flare the pins open by maybe .005-.010" to help engagement with the female socket? Do you think this would work or do you know of another way to correct this issue?

    Has anyone else had this issue or know of a solution?
  6. plowguy43

    plowguy43 PlowSite Fanatic
    Messages: 5,264

    I had that issue with an older fisher. I put them together and used some pliers to squeeze them together. Worked after that, not sure how it'd work on the Snowdogg though
  7. Ram 08

    Ram 08 Member
    Messages: 53

    After digging deeper the problem appears to be in the plow side harness. It must be in the wrapped portion of the harness because I can't see any wire damage in the power unit and everything is clean and connected. The weird part is that when I connect my meter to the pin (orange wire S3) in the plow connector I have continuity to every other pin in the connector. Has anyone seen this type of failure before?
  8. hedhunter9

    hedhunter9 Senior Member
    Messages: 212

    We have seen several with breaks in the wires... Several with only a few strands of wire connecting... We had blinks, but the plow worked...
    Finally stripped the wire and found only 3 strands of wire in the middle of the harness. Came from the factory this way....
    Repaired it and the blinks went away.... Cheap chinese wire prob....

  9. Ram 08

    Ram 08 Member
    Messages: 53

    Update just in case someone else has this issue. The problem was a broken orange wire inside the harness right at the crimp where it connects to the three orange conductors for S3A/B and relay module.