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Pump Screeches Won't Lift Plow

Discussion in 'Western Plows Discussion' started by mtnxtreme, Jan 13, 2015.

  1. mtnxtreme

    mtnxtreme Member
    Messages: 55

    I have a Western Unimount with the isolation module style pump. When I try to lift the plow you can see the pump jump, and it kinda screeches a little but won't lift the blade. If I keep clicking the joystick button, after like 30 tries all of a sudden it will lift. Once up if I hit the left button it goes right and if I hit the right button it goes right, seems like the right button is the only thing that works. Then i drop the plow and I'm back to square one, it won't lift. Any Ideas ?
     
  2. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,972

    Wait....what plow do you actually have?
    Let's start there.
     
  3. mtnxtreme

    mtnxtreme Member
    Messages: 55

  4. cubicinches

    cubicinches PlowSite.com Addict
    Messages: 1,412

    From your description, it sounds as if you've got cartridge valves which are not activating correctly for the requested function. I'd start by trying another controller first, as those symptoms are indicative of a bad controller. If that doesn't fix it, you've likely got a truck side or plow side control harness which is shorted or has a broken wire... likely at or near the three pin plug. Also, remove the cover over the cartridge coils and make sure one of them doesn't have a wire that's come disconnected.
     
  5. mtnxtreme

    mtnxtreme Member
    Messages: 55

    If a wire was bad or shorted it should do it all the time ? Every once in a while it works, like somthing is sticking ?
     
  6. cubicinches

    cubicinches PlowSite.com Addict
    Messages: 1,412

    That's correct... most likely the S3 valve is not shifting (again, based on your description), there's about 20 reasons why that could happen. I just gave you three of the most common ones. And broken wires in the control harness can certainly cause intermittent issues, because they're broken only enough to intermittently lose contact.
     
  7. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    Lets get the plow identification and terminology sorted out. You have a unimount plow (probably a heavy weight because that's the only uni I know of that came with the isolation module. All others, to the best of my knowledge, came with relay headlight control. The pump, or "hydraulic unit" is called Isarmatic. The pump is not isolation module type, the electrical system is. You probably have the four port isolation module (a black electrical box with four plugs that switches the headlights from truck to plow) Since it has the isolation module it will have three plugs at the grill, one for switched power to the pump motor, one with three pins for the three valves and finally an 11 pin plug for all the lights.

    So... when you talk about your plow, if my assumptions are all correct, you have a unimount, straight blade with the three plug (at the grill) four port isolation module.

    As said above, I would start by trying a known good controller. If a good controller doesn't change anything then you need to look at the controller harness, the three pin plugs and the plow side control harness. This is an analog system, that means there is a dedicated wire for each of the three valves and one common ground. It could also be that one of the valves is sticking. The screeching sound suggests that the pump is going over the pressure relief valve. That means either valves are stuck shut or they are simply not being sent a signal to open. Could be electrical or mechanical. You need to try each function, figure out which valve should be active and then test the appropriate coil for magnetism. You can just hold a ferrous metal screwdriver to the end of the coil / valve and feel for attraction. If the wires are OK and the coil is good you will feel that magnetism. if all three valves magnetize when they should you need to start replacing valves.
     
  8. mtnxtreme

    mtnxtreme Member
    Messages: 55

    OK I checked it, it has one plug with 2 heavy terminals and another plug with 9 small terminals, it looks exactly the same as the one in the manual link I posted so I guess it is an Isarmatic. I was able to download an entire repair manual from Western website, I will keep you posted as to what I find.
     
  9. xgiovannix12

    xgiovannix12 PlowSite.com Addict
    Messages: 1,419

    How about take a photo of the plow for us
     
  10. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    If it has 9 pins on the one plug its not an isolation module unit, it's a relay system. There were two relay systems one with 9 and another with 12 pins.
     
  11. mtnxtreme

    mtnxtreme Member
    Messages: 55

    I dont know I been using this manual for Isarmatic, the pump, all parts are exactly the same as mine and it shows a 9 pin plug for the earlier models ?
     
  12. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    The manual for the relay and the isolation module will be the same as far as the Isarmatic pump goes. The electrical is the only difference. Here is a link to the mechanic's guide for the relay Isarmatic. It shows the 9 and 12 pin electrical. The headlight relays shown may not be right but the function controls are the same for all relay systems. It's just three wires, one for each valve, and a common ground to all three valve coils. Since you have functional problems and not light problems you can rely on this manual. What you need is the diagrams of the hydraulic paths and the valve activity table.

    http://library.westernplows.com/westernplows/pdffiles/21936_121704.pdf

    In the future when you ask for help identify your unit as a Western uni-mount straight blade with Isarmatic pump and 9 pin relay electrical. Then people will know exactly what they are dealing with....Thumbs Up
     
  13. mtnxtreme

    mtnxtreme Member
    Messages: 55

    Ok thanks I'll dig into it this weekend!
     
  14. mtnxtreme

    mtnxtreme Member
    Messages: 55


    Mishnick this is probably a dumb question but when you say end of coil, do you mean outside where wire attaches, or do I pull it out and test the inner end ?
     
  15. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    The only dumb question is the one not asked.... The coil is mounted on the valve and a nut holds it on. When the coil is magnetized the valve becomes the magnetic core. So leave the coil on the valve and just hold a screwdriver or something close to the end of the valve as it sits. You will feel, when you touch it, if it is magnetized, the screw driver will stick but when the power stops flowing it will not.
     
  16. mtnxtreme

    mtnxtreme Member
    Messages: 55

    Tested all 3 cartridges as per the shop manual and the S2 is barely moving, the other 2 have travel, and the S2 barely moves, also tested the coils all 3 good, so I'm gonna order one up, hoping I got it !!
     
  17. mtnxtreme

    mtnxtreme Member
    Messages: 55

    OK changed the cartridge still not working ugh I thought I had it. flushed fresh fluid no good !!!!The motor spins but plow dont move, every once in a blue moon it lifts a few inches and stops, definite sound change when it lifts, sounds kinda electric only when it dont lift then when it lifts get noticeably louder and you hear the pump kick on, maybe the pump is bad ? I gotta study the manual tonite, any ideas, things t check for ?
     
  18. xgiovannix12

    xgiovannix12 PlowSite.com Addict
    Messages: 1,419

    check pressure
     
  19. cubicinches

    cubicinches PlowSite.com Addict
    Messages: 1,412

    When you changed the fluid, did you pull the motor and pump and check the pickup screen? Or did you just drain it and refill it?
     
  20. mtnxtreme

    mtnxtreme Member
    Messages: 55

    That was my next thought ! And yes i cleaned the screen !
     
    Last edited: Jan 24, 2015