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Strange MM2 no power issue

Discussion in 'Fisher Engineering Discussion' started by Motorman 007, Jan 2, 2014.

  1. I have a friend who has an 8' straight blade MM2 3 Plug Insta Act 3 port on a 2011 Chevy 2500HD. When he attaches the plow to the truck the headlights don't switch over and there is no power at the fishstick so obviously the plow doesn't work at all. Battery connections are good. Ground on the blk wire with the orange stripe is also good. There is 12V on the red wire that powers the Fishstick. There is power at the fuses in the harness that connects to the "C" port of the iso mod. There is NOT power at the fuses in the other harness. If I jump the solenoid the plow motor runs. If I tap the iso mod the truck lights flicker slightly. Any ideas?
     
    Last edited: Jan 2, 2014
  2. kimber750

    kimber750 PlowSite Veteran
    Messages: 3,570

    Is the smaller red wire on the battery side of solenoid?
     
  3. I will look. Which smaller wire do you mean? Nothing has changed, the plow worked fine last week.
     
  4. kimber750

    kimber750 PlowSite Veteran
    Messages: 3,570

    Thought this was an install. Check bumper connections. Check that small red wire of large terminal on solenoid. This wire powers the plow system.
     
  5. thx Kimber. I will ck that. I feel as though I have a pretty good handle on these insta acts but this has me stumped.
     
  6. Power is good to that wire. Took it off and cleaned it anyway. Still have no power to the two fuses in the vehicle control harness (3 pin) one is a 15 amp for the park/turn and one is a 7.5 amp for the straight blade control. Double checked keyed power to the joystick and it is good......
     
  7. kimber750

    kimber750 PlowSite Veteran
    Messages: 3,570

    Got to be a broken wire. That red/green wire goes right to those two fuses. If it is hot at one end and nothing at the other has to damaged.
     
  8. here is the schematic...what does the relay or square box that I have circled that says "not Used" do?
     

    Attached Files:

  9. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,924

    Nothing. Not for your setup
     
  10. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,924

    If the 2 fuses you have labeled "no pwr" have no pwr. You gotta have a broken wire like kimber said. They get pwr straight off the batt
     
  11. Got it...

    Thanks for the help guys. I figured it out once I actually had MY eyes on it. It turns out, the fuses without power were the two ten amp fuses in the Fisher lighting harness. It took a lot a lot of looking but once I cut the wire ties that the installer put on the excess wire in the fisher harness I found a very small amount of green corrosion dust on the harness which further revealed a disintegrated wire in the fisher harness right near where the factory lighting harness plugs into the fisher harness. I had to remove the grille but it made it easier to repair.
    I have re-sent my diagram with corrected notes and the double circles are around where I found the problem in case it ever happens to someone else.
    Not your ordinary fisher issue for sure....
     

    Attached Files:

  12. unhcp

    unhcp PlowSite.com Addict
    Messages: 1,243

    sounds like something to do with the headlight connectors or maybe a bad module??
     
  13. The resolution is above. The module was fine.