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no power out of motor relay???

Discussion in 'Fisher Engineering Discussion' started by liftedgmc05, Feb 23, 2012.

  1. liftedgmc05

    liftedgmc05 Junior Member
    Messages: 26

    I put a new motor relay in the truck and hooked a red jumper wire up from one of the small terminals on the relay to the batt post on the relay and when I went to plug the power wire up the plow started turning so I took the red jumper off and it worked fine a little while later I hooked it up again and I have no power coming out of the relay to the plow but there is power to the relay and on a meter it shows when I push the controller button,

    I was wondering if I can put a jumper wire from the batt terminal on the relay to the other power post on the relay that has the red power wire that goes to my plow motor thanks
     
  2. Kopper10

    Kopper10 Sponsor
    Messages: 50

    What kind of plow do you have?
     
  3. liftedgmc05

    liftedgmc05 Junior Member
    Messages: 26

    its a 8' 3 plug fisher mm 1 with a sehp pump on a 2005 gmc 2500hd
     
  4. Kopper10

    Kopper10 Sponsor
    Messages: 50

    Where did you get your motor relay? I don't believe you should have a jumper.

    You should have a black/orange wire and a brown/red wire that connect to the small terminals. There should also be a red/green wire that should go to the hot side of the large terminal.
     
  5. liftedgmc05

    liftedgmc05 Junior Member
    Messages: 26

    yeah i have all those, and i have power to the relay just no power going out to the plow, so i was wondering if i could take a jumper wire to jump the two top terminals on the relay to send power to the plow
     
  6. Kopper10

    Kopper10 Sponsor
    Messages: 50

    I believe that would be a valid test to determine if your problem is not in the battery cable or the motor itself.
     
  7. liftedgmc05

    liftedgmc05 Junior Member
    Messages: 26

    ok thanks i just wasnt sure what would happen and i didn't want to burn any wires up or anything I will try it and let you know thanks again
     
  8. If your truck is set up the way it was in your previous threads with an Iso Mod 3 plug system on the truck, I don't believe an SEHP MM1 plow will work with it. You need the Insta Act pump setup.
     
  9. 2006Sierra1500

    2006Sierra1500 PlowSite.com Addict
    Messages: 1,758

    Which pump?

    [​IMG]

    [​IMG]
     
  10. chevyzrule810

    chevyzrule810 PlowSite.com Addict
    Messages: 1,238

    A SEHP will work on a 3 plug truck.I repainted a mm1 8 foot with an SEHP pump on a 2010 F350 and it didn't have a problem.As long as the plow is converted it will work on the truck.
     
  11. Exactly. If he installed the proper 3 plug harness on the plow side, he shouldn't have to be "jumping" anything to make it work properly. He's had 2 or 3 different threads going in the last 6 weeks about 2 plug and 3 plug plows and whether they will work on his '05 2500HD with a 4 port iso system.
     
  12. chevyzrule810

    chevyzrule810 PlowSite.com Addict
    Messages: 1,238

    make it easier on all of us and convert the plow to a 3 plug already. I'll convert it for you
     
  13. Buster F

    Buster F Senior Member
    Messages: 208

    If i recall correctly the op has a 3 plug plow which he somehow had working with no plow lights connected to the 11 pin plug. I have owned and installed many Fisher 3 plug plows and assembled more than a few from parts collected from here and there and can say that i've never had one that would function without plugging in the 11 pin lighting harness. This leads me to believe that somewhere along the line the op's wiring on the truck side has been tampered with and could very well be what is causing the current issue with the relay. Might be something to take a look at.
     
  14. chevyzrule810

    chevyzrule810 PlowSite.com Addict
    Messages: 1,238

    I thought it was funny when he said that the plow works without plugging in the 11 pin harness as the 11 pin controls the plow and the lights. If he wants to use the truck lights instead of the plow lights I wonder what would happen if he plugged the 11 pin harness in and didn't plug any of the plow harness plugs into the factory light plugs.Seems to me like he would still have power to the 3 valves and ground?
     
  15. Buster F

    Buster F Senior Member
    Messages: 208

    I don't know what will happen if you don't connect the wires from the #3 and #4 harnesses on the iso mod, but i do know that i currently own 3 trucks with 3 plug setups and the controller will not work without the 11 pin light harness connected.
     
  16. liftedgmc05

    liftedgmc05 Junior Member
    Messages: 26

    my plow works fine!!!! no headlights my truck is lifted so I use the headlights on my truck and yes it is a 3 plug set up I have all three plugs coming out of the grill of my truck but i do not have any headlight harnesses wired into my lights,not sure why I didnt have any power coming out of my motor relay but I bought a new one and installed it and the plow works fine and I havent had any issue, by the way the wiring in my truck is brand new and never been tampered with,except for the module that is used and its out of a Ford and it works fine in my GMC 2500HD
     
  17. Glad to hear you are all set.

    Having said that, it is my experience that a properly installed 3 plug isomod system WILL NOT operate unless the 11 pin lighting harness is connected. Just sayin'