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Problem with western 3 plug plow stops working

Discussion in 'Western Plows Discussion' started by jasonz, Jan 3, 2014.

  1. jasonz

    jasonz Senior Member
    Messages: 250

    So here are the specs

    2006 f750
    western 10' heavyweight
    truck has three plug wiring with three port iso mod
    plow was converted to three wire with nighthawk lights

    Last night was the first time we used the plow other than transporting it for the most part. Driver said after twenty minutes of use the controller shut off and he could not move the plow, then it started to work again a minute later, this happened two times more but the last time it did not come on.

    what I checked:
    Signal wire for switched accessory is good and has power
    all plugs between truck and plow were dry and tight
    tried a new controller and new solenoid

    when putting a test light on the truck side of where the controller plugs in each wire had power going to it (with no controller plugged in)

    when putting a test light on the solenoid the battery side was very bright however even when not pressing anything on the controller the "output" side of the solenoid had weak power (test light was dim)
    when we unplugged any of the three plow plugs the output side had no power
    I also remember hearing what i thought was a clicking in the iso mod box.
    controller power light was off.

    Also plow lights were off truck lights were on

    All wiring other than the battery cable on the plow is new, solenoid was new controller was working complete truck side wiring was new. I wired it the same as Ive wired 7 other setups that all preformed great last night.

    Any Help would be great I have another plow I can test on the truck and another truck I can test this plow on but I don't want a faulty part to damage anything else.
     
    Last edited: Jan 3, 2014
  2. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,983

    Hook plow back up. Test light the small signal wires. See if the clicker is sending pwr to one of them. The other small wire is yout gnd. f you have that signal, then ck th. Output big wire for pwr there. Then move to the plow motor. Ck for pwr while up, left or right is pressed. Also look at your gnd.
     
  3. jasonz

    jasonz Senior Member
    Messages: 250

    clicker=controller? what i am saying is it seems something is back feeding the controller because with the controller unplugged all of the wires on the truck side of that plug have power.
     
  4. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,983

    Yea. It could very well be the back feeding, solenoid or the plow motor, a bad gnd,
     
  5. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    Sounds wonky that u have power at the controller plug. Dumb question but r u sure pos and neg cables r connected correctly at battery? Also check the ground interconnect at the isolation module. Two black wires with orange tracers. They have black plastic quick connectors and may not be securely connected. This plug completes the plow presence detector circuit and must be connected or the controller will not fire up.
     
    Last edited: Jan 3, 2014
  6. jasonz

    jasonz Senior Member
    Messages: 250

    I doubt its the controller seeing as how I swapped in a brand new one and it did nothing also even with no controller attached there is power where there shouldn't be,
     
  7. jasonz

    jasonz Senior Member
    Messages: 250


    Ok anything else? Im going to check every connection on the harness and Im sure the cables on the battery are correct the plow did work a few times before.
     
  8. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    The feedback u speak of concerns me. If battery cables r right b sure big plug at grill is oriented correctly. They have a key but can b forced in backwards. Just to b sure...
    Not sure exactly what plow you have but if it's ISO module with three plugs then it can b normal to have power at three pins of controller plug because the three valve coils have common positive and the controller completes the circuit to ground. This will certainly cause an LED test light to light up bright. An incandescent test light would glow yellow. But are there only four pins in your plug? I don't have my book here so I am not sure but I thik there should b six pins.
    One more thing is to check the ground wire, if it has one, on the plow going from one of the two lite (small gauge wire) wire harnesses to the negative lug of the pump motor. Again black with orange tracer.
    I keep coming back to a bad ground when I think this through because your test light glowed on the output side of the motor relay (solenoid). If u have a good ground from plow motor ground lug to battery negative that should never glow there unless the relay is activated. U could try putting a booster cable from motor negative lug straight to vehicle battery negative post. This would give u an extra path for ground and bypass the grill plug. Just a quick trick to eliminate that plug.
     
    Last edited: Jan 4, 2014
  9. jasonz

    jasonz Senior Member
    Messages: 250

    ok

    so I tried a few things today while I was at my yard.

    first of all when I first got there after the truck had sat all night it worked fine for a minute, after about the third movement of the joystick it shut off.
    I checked that ground connection near the iso mod that someone mentioned and its fine all other connection look good too. None of the wires a chaffed or anything.

    heres where it gets weird

    when you touch a test light to the red/brown wire on the motor relay ( the signal wire I believe ) it has weak power and something in the iso mod clicks.

    Also if you unplug that ground wire near the iso mod one side has power ???? and touching a test light to it also makes the iso mod click.

    I swapped the iso mod with another truck and the "bad" one worked in that truck and the "good" one did the same thing in the truck with the issue.

    at some point it must have reset itself after turning off power and unplugging some of the plugs at the iso mod because the controller had power so I disconnected the power wire to the pump motor and tried using the controller, the relay clicked and made noise and the controller shut off. Hook the pump wire back up and it clicked and shut off. Tried another pump same thing.

    Again as far as I can tell nothing is cut or chaffed I even tried pulling the wires off the coils on the pump that didn't seem to have any effect.

    I am stumped. Its something to do with that control wire I think and why would that ground wire have power?
     
  10. jasonz

    jasonz Senior Member
    Messages: 250

    also all the fuses in the system are fine.
     
  11. Whiffyspark

    Whiffyspark 2000 Club Member
    from SOMD
    Messages: 2,402

    Try using jumper cables.

    Ground of battery to ground on pump.

    Then try positive side.

    You have to have a wire or something chaffed, broke etc.

    The only other thing I can think of is a bad motor, but that usually wouldn't shut the controller off. (Someone correct me on that if needed please)

    You could also try testing continituy through the control harness
     
  12. jasonz

    jasonz Senior Member
    Messages: 250

    why would the ground wire near the module have power?
     
  13. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    The ground wire by the ISO mod will have power only if the plow light plug is connected at the grill, and the black ground plug at the ISO module is seperated, and then only on one side. This is the plow presence circuit. Power is applies to the coil of a relay in the isolation module. The other side of that coil goes out to the plow light plug. If the plow is connected that signal goes through the plug and is looped right back around to the truck and then finds it's way to battery negative via that black plug. So if u unplug it there will b power on one side. This is good because it should make the isolation odule click indicating that the plow is recognized. This tells me your plow headlights should b coming an and truck lights go out when plow is connected.
    Did u check at the motor relay to see that the positive feed wire is good? There r two small wires going to the coil lugs (small ones) and a third small gauge wire going to the always hot large lug. This wire feed 12v to the two fuses at the ISO module. You say the fuses r ok. Did u verify your test light lights up at the fuses or just look at them. Check the fuses with the light when the plow is dead. If they r not hot it's that positive feed wire between the fuses and motor relay.
     
    Last edited: Jan 4, 2014
  14. jasonz

    jasonz Senior Member
    Messages: 250

    I did not test light the fuses but when I would pull one out and put it back in the iso mod would click it also clicks when you put the test light on the signal wire at the motor relay, why does it do that? and why when the plow is dead is there power at the not hot big lug? that should be dead unless the controller is telling it to open right? FYI when the plow is dead the plow lights also do not work. the entire truck side of the harness is brand new the light and control harness is brand new as well only the power cable on the plow is used.
     
  15. jasonz

    jasonz Senior Member
    Messages: 250

    also why would it work after sitting for a period of time?
     
  16. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    I suspect your hot relay wire is normal because it has a common positive. When u hit the control buttons for anything but down the other side of the coil is grounded by the controller.
    Not sure why module clicks when u test the relay with light.
    But being hot on output (cold) side of relay indicates bad ground between pump motor negative and battery negative. Do the booster cable thing. Jump between motor ground lug and battery negative post. And have a good look at the heavy power plug at the grill and the plow half of that cable going to the motor.
     
  17. jasonz

    jasonz Senior Member
    Messages: 250

    so with the jumper cables "bypass" from the pump ground terminal directly to the battery negative terminal?
     
  18. Whiffyspark

    Whiffyspark 2000 Club Member
    from SOMD
    Messages: 2,402

    Yup. Can do neg side to check for a bad cable, but stand clear of the blade
     
  19. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    Yes exactly. Tis should not spark at all. You r just doubling up on the ground.
     
  20. jasonz

    jasonz Senior Member
    Messages: 250

    so if this works either my ground is bad on the truck or the power cable on the plow? since its a large truck I had to ground it to a bolt on the frame because the batteries are mounted in the battery box under the cab. I did grind the paint off around the bolt and wire wheeled the bolt. Also it seemed to work fine for a while. Anytime I moved the plow around in the yard and when I brought it back from the body shop.

    this problem is driving me nuts Im tempted to drive back to my yard and try jumping it tonight