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Fisher MM1 EZV Lowers suddenly

Discussion in 'Fisher Engineering Discussion' started by Clint S, Feb 11, 2008.

  1. Clint S

    Clint S Senior Member
    Messages: 280

    When driving down the road today the plow just suddenly lowered by itself. Scared the S@#$ out of me as snow came over the blade and temporarily blinded me. The fish stick was on the seat next to me so it did not get bumped. It did it one more time today and then would not go up. So I went out front and kind of jiggled all the wires shut the truck down waited a few minutes and started her up and now everything seems to work. Big question. Could a loose corroded connection cause the plow to suddenly drop. Not going up is one thing, but suddenly dropping when driving down the road scares me. Worked fine to clean up 3 driveways tonight. I am just thinking that a bad connection would not cause it to drop. Not go up yes, but drop? I really have no clue.
     
  2. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Internal corrosion in the grill plug, short in wiring harness or a faulty Fish stick can all cause it to drop unexpectedly as the coils/valves on the EV's are triggered by ground, not 12V power as most plows are.
     
  3. Clint S

    Clint S Senior Member
    Messages: 280

    Thanks I did not know that. The grill plug looked good this fall, but who knows. Since wiggling the wires fixed it, I will start there. Would putting the plow up and then turning the power off at the stick prevent this from happening until I find the problem. I have had friends that have had problems with their fish stick, but they are a little expensive to just go out and buy one.
     
  4. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Is is an Iso system or the old relay system? If it's a relay setup, since the coils are powered all the time and then tripped by ground, any short to ground in the Wht/yel and Lt green wire could cause it to lower.

    If it's an Iso system then more than likely it's a faulty controller.

    Never hurts to keep it turned off when not in use either way though..
     
  5. Clint S

    Clint S Senior Member
    Messages: 280

    It was new in 03. It is an EZV minute mount 1. I think and there is an isolation module under the hood if that is what you mean. This fisher set up is far more complicated than my meyer set up on the 95, BUT it has been way more reliable until this little glitch.. Maybe I will try tapping on the controller tomorrow to see if it goes down without pushing the button as well as pulling apart the connections.
     
  6. Clint S

    Clint S Senior Member
    Messages: 280

    This has continued to happen a few more times. I have examined all the connections and looked at the harness under the hood and it SEEMS fine but do not know. I can take the stick and tap on it pretty good and the plow does not go down. Yesterday when backing into the garage, the plow lightly brushed against the door frame and I mean lightly and the plow lowered and would not go up. Went inside came back out later and it all worked fine. Took off all the plastic caps and all the solenoid connections look ok too, although a red wire on one of them was partially off. It was on the pass. side solenoid on the one with 2 solenoids on it. Should I still keep looking at the stick or look at the wiring in greater depth. An help would be appreciated. Clint
     
  7. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    As a test you'll want to consider unplugging the controller any time your not actually using the plow. See if it still drops on it's own. Do see controllers go bad a lot on the DD plows.


    I'd do whatever I had to to diagnose it as it's definitely a safety issue the way it is now.
     
  8. Clint S

    Clint S Senior Member
    Messages: 280

    I will unplug the controller whenever I am not plowing and see how that goes. If it goes down then it has to be in the wiring. The connector at the bumper looks fine and is still filled/coated with this falls dielectric grease. What solenoid controls up/down. I will start there and trace back from there. This is our farm truck and my dad plows with it way more than I do as he is retired and I work at the hospital all day. He does not pay attention to things like I do. I do not think it has went down with the power at the stick turned off, but we will disconnect it when not plowing.
     
  9. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    S1/S3 control drop..

    If your not sure the controller was off when it dropped then I'd be akin to believe it's a faulty controller.
     
  10. Clint S

    Clint S Senior Member
    Messages: 280

    I am 99% sure the controller was on each time it dropped. Not sure with my dad, but the 2 times it did it with me it was on. My dad thinks it is not the controller because he was holding it steady in his hand the last time it happened, I tried to explain to him it would not have to be a big bump or a jar to cause it trigger as I think there is a small circuit board in there and it could easily just be triggered by road vibration if it get touchy (am I on track with this) and the reason it would not go up a few times with him after falling was that the down button was "stuck" on and shutting down the truck powered down the system and when the system was powered back up the down button could have been "released". I told him to see if the float light was on the next time it goes down and not up as that would let us know that the button was activated for a length of time to put it in float mode.(am I on track with this). I will convince him to unplug it every time he goes down the road and if that is that we will buy a new stick as the bumper plug looks fine and there are no visible damage to the harness. Thanks for the continued help. Clint
     
  11. Clint S

    Clint S Senior Member
    Messages: 280

    Another quicky are those coils on the bank of 1,2 or 3 solenoids. My parts break down only shows the part #. Edit I checked it is the bank of 3. If it is the controller would it be the PCB I had to replace.
     
    Last edited: Feb 16, 2008
  12. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Your on the right track with your thinking Clint. I had an MVP one time that the owner said it sometimes wouldn't raise. (owner failed to mention that it would also retract the right wing without warning sometimes).

    Since I was working on the system, I had the controller on and it was lying on the seat. Had no choice but to stand behind the blade to work on the coils/wiring/grill connector assemblies (plow was on the ground of course though)...and without warning the right wing retracted all by itself, didn't even have a hand on the truck.

    Still have the mark on my leg 2 years later...


    So it's entirely possible that a defective controller can cause unwanted plow movement...Thats why I suggested unplugging it when not in use until you pinpoint it for sure.

    The S1 (wht/yellow wire) and the S3 (Lt green wire) are in the row of three valves in the primary manifold.
     
  13. Clint S

    Clint S Senior Member
    Messages: 280

    Thanks alot I will troubleshoot this and hopefully let you know how it works out. I live near syracuse NY and we have lake ontario to thank for at least 5 or 6 1 plus foot dumps every year. The biggest one this year was 41 inches and 20 miles north or south got ZERO. Last year we got 120 inches in 4 days. We get well over 200 inches a year and have to plow alot. My dad and I do the farm my house 3 brothers and sisters, granny's and a couple of neighbors who could not get out if it was not for us. We have a 95 150 with a meyer that was pretty much junk from day one. Finally just replaced the whole power head, and the ezv on the HD. Been a great plow until this little problem. Also have a 4x4 tractor with a bucket for moving it. When it gets too deep. Thanks again Clint.