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MM1 Harness on 2004 GMC from 1996 GMC

Discussion in 'Fisher Engineering Discussion' started by Tumas, Oct 27, 2009.

  1. Tumas

    Tumas Member
    from NFLD
    Messages: 51

    Can I use this harness off my 1996 on my 2004?? Where can I find a wiring diagram for this if it is possible? Or will I have to buy a whole new harness/controller?? I hauled a mess of wires off my 96 today and dont really know where to start with my 2004..?
     
  2. RepoMan207

    RepoMan207 PlowSite Fanatic
    from Maine
    Messages: 5,031

    Well, it would help to know which harness or harnesses you have.?.?.?

    How many plow connections is there, and how many pins in each? If only two connectors, is there 9 pins in one and 2 pins in the other?
     
  3. Tumas

    Tumas Member
    from NFLD
    Messages: 51

    yes you are correct it has a 2 plugs one is a 9 pin for the lighting and the other is a 2 pin to run the pump im assuming. I believe I have the original fisher relay harness. It has no iso. module
     
    Last edited: Oct 28, 2009
  4. RepoMan207

    RepoMan207 PlowSite Fanatic
    from Maine
    Messages: 5,031

    Yup, you can wire your truck with it. I just pulled mine out this past weekend on my 02. It was like a big a** hair ball once I got it out.

    Mine had another tail off the harness, it went to the headlights on both sides of the truck...not seeing it on this diagram though.


    Here, this might help..... View attachment SHEP troubleshoot.pdf

    [​IMG]
     
  5. Tumas

    Tumas Member
    from NFLD
    Messages: 51

    Thanks that will help a lot... Did you get your DRLs to work? My they didnt seem to work on my 1996, or maybe it just wasent equipt with them
     
  6. Crash935

    Crash935 2000 Club Member
    Messages: 2,377

    harness off the 96 will not work on the 04
     
  7. Tumas

    Tumas Member
    from NFLD
    Messages: 51

    I believe it will. You have to remember I only have the original Relay type harness. I have no isolation module
     
  8. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Doesn't matter, you still have to update the old 9 pin to the newer (but still obsolete) 12 pin if you want to continue to run the old relay system. The 9 pin is NOT compatible.
     
  9. Tumas

    Tumas Member
    from NFLD
    Messages: 51

    why is it not compatible and what will I have to buy to make this work? Repoman said he has done it?
     
  10. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    The 9 pin ties the two sides together which you can not do on an '03 and newer GM truck. The 12 pin keeps the left and right independent...like they're intended to be.
     
  11. Crash935

    Crash935 2000 Club Member
    Messages: 2,377

    Doing it from memory but it should be a 64077 harness (truck side) and 64078 headlights (plow side)
     
  12. Crash935

    Crash935 2000 Club Member
    Messages: 2,377


    And he took his off a 02 which is also different than a 96.
     
  13. Tumas

    Tumas Member
    from NFLD
    Messages: 51

    So will I be able to use my controller or is it all different?
     
  14. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Yes you can reuse it. It will be the rest of the wiring that you'll be changing.
     
  15. Tumas

    Tumas Member
    from NFLD
    Messages: 51

    What approximatly will this run me price wise? Any idea? I will have to make a trip to town to purchase the kit on friday.
     
  16. Tumas

    Tumas Member
    from NFLD
    Messages: 51

    What I dont understand is my harness seems to look identical to the harness in the diagram posted above?
     
  17. Crash935

    Crash935 2000 Club Member
    Messages: 2,377

    Call ahead, they will probably have to order it.

    B&B - just want to make sure im right on the #'s.
     
  18. Crash935

    Crash935 2000 Club Member
    Messages: 2,377

    It is, but thats not the one you need. Repoman is usually right but weve got him on this one so go with B&B and myself on this.

    And where is NFLD?
     
  19. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Looking at about $400 for everything.

    Crashs memory is good but his 64078 p/n wasn't quite correct. That would be the harness and the plow lights both. You'll only require the harness, which is p/n 61558. He was close though. :drinkup:
     
  20. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    They all look the same in a picture because it's a generic pic. They're far different when viewed in an actual wiring diagram.