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Fisher MM1 Plow Lights Not Switching Over.

Discussion in 'Fisher Engineering Discussion' started by SolsticeLandscp, Jan 20, 2013.

  1. SolsticeLandscp

    SolsticeLandscp Junior Member
    Messages: 17

    Hi All,

    I installed new 9 pin plugs on my plow and now the plow headlights don't work. Everything else does and when I run a wire from the battery to the black wire on the solenoid the plow lights work. So it seems like for some reason they are just not getting the signal to switch over. Any ideas on how to fix this? I can hear the solenoid click so I assume its okay. Thanks for any help.
     
  2. RepoMan207

    RepoMan207 PlowSite Fanatic
    from Maine
    Messages: 5,038

    9 pin...so you have a relay setup? Sounds like a bad relay.
     
  3. SolsticeLandscp

    SolsticeLandscp Junior Member
    Messages: 17

    There is a solenoid do people refer to that as a relay? It seems to work fine for everything else, would just one part of it break like that? Thanks for the reply.
     
    Last edited: Jan 21, 2013
  4. RepoMan207

    RepoMan207 PlowSite Fanatic
    from Maine
    Messages: 5,038

    ahh, yes and no, that is a motor relay you're thinking of, a.k.a solenoid. What I'm referring to is the light setup, is it a group of relays, or an ISO module setup? You have 2 grill connectors at the bumper?
     
  5. SolsticeLandscp

    SolsticeLandscp Junior Member
    Messages: 17

    Yes two plugs. I can see two relays where an extra battery would be. Are there more?

    Plowrelay.jpg
     
    Last edited: Jan 21, 2013
  6. SolsticeLandscp

    SolsticeLandscp Junior Member
    Messages: 17

    To clarify things I ran a wire from the battery to the black wire on the relay I am holding in the above picture. All the lights work when it is hooked up. There are no high beams though, not sure if there ever was.
     
  7. RepoMan207

    RepoMan207 PlowSite Fanatic
    from Maine
    Messages: 5,038

    I cant view the attachment...


    There is motor relays, then there are relays...

    [​IMG]

    [​IMG]

    I'm talking about the later. You have an older style setup that is controled by a series of relays, rather then ISO..

    ISO Module.

    [​IMG]

    Here is a crappy photo of what your relays probably look like all taped up (one or more of these is most likely junk, hence your issue).


    [​IMG]
     
  8. RepoMan207

    RepoMan207 PlowSite Fanatic
    from Maine
    Messages: 5,038

    I can see it now...yes, replace these. There should be more...what kind of truck?
     
  9. SolsticeLandscp

    SolsticeLandscp Junior Member
    Messages: 17

    Thanks for the pictures. It is a 99 Chevy k2500. I will look for and test more relays tomorrow.
     
  10. SolsticeLandscp

    SolsticeLandscp Junior Member
    Messages: 17

    Before I start removing too much from the front of the truck, any ideas where the additional relays may be?
     
  11. RepoMan207

    RepoMan207 PlowSite Fanatic
    from Maine
    Messages: 5,038

    EDIT: Just replace that relay that you're holding in the above photo. If it still doesn't work, then there is a loose connection...either from a broken or compromised wire, or the solenoid (Motor relay - first photo I posted above) isn't hooked up properly. You said...
    . The "S" on plugs is throwing me off...did you replace truck side too, or just the plow itself?

    (Original post)

    Just follow the 9 pin harness from the grill. Depending on what body style you have (type of lights), those maybe your only two. 99 GM's had 3 different light setups if I remember right...I know 2 for sure. You might want to start by just replacing those and see where you're at.

    Also...I'm sure it's just a burnt up relay...but this may prove useful.


    [​IMG]


    [​IMG]


    [​IMG]
     
    Last edited: Jan 22, 2013