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Plow Lights - My HOT POTATO

Discussion in 'Fisher Engineering Discussion' started by Nitrousguy, Mar 11, 2012.

  1. Nitrousguy

    Nitrousguy Junior Member
    Messages: 7

    Ok here’s what is going on. My friend has a 2006 f-250 with a MM2 plow. 3 plug 3 port(white label ) harness. When the plow was first installed everything worked. Then this year when he plugged it in the red light on the joystick would not go on. He returned to the place that installed it and they (hot wired) it in the cab. They force powered the control box with an additional red wire. They told him that probably the control module went bad and was not powering the control box. Well when he went to turn the night on at night only the truck headlight stayed on. So now his headlights don’t work and the box wiring is hacked. He has now asked for my help.
    This is what I have tried:
    I connected his plow to my truck with and all lights and movements work fine(not a plow side problem)
    I installed his 3 port module in my truck with his plow – everything works fine ( not a module problem)
    Checked all light connections on his truck and plug connections in his harness – they are tight and all match my truck.
    My next step was to remove all wiring harness and test all connections with test light. Seems like a lot of work. but the reason for post is – is there something I’m missing before I go through the trouble of removing all the wiring?
     
  2. chevyzrule810

    chevyzrule810 PlowSite.com Addict
    Messages: 1,238

    Welcome to plowsite! Seems to me like its all wiring harness and no isolation module or plow problem.First question-Where does that additional red wire go to and from? Second question-does he have an add a fuse installed in the truck like this:
    [​IMG]
    If he doesn't I would figure out where they have hot wired the red wire control power wire and get rid of the fubar completely.Then I would go and buy an add a fuse (like the one pictured above, get it at autozone,advanced auto and even radio shack.Your also going to need to buy a 10 amp fuse to use for the plow fuse so get a few just for backups.Then go into the fuse box inside the truck and find a key on fuse.This is so when the truck is shut off the plow isn't still getting power.You can use the radio,cruise control etc.Once you figure out which fuse you are going to use remove it from the panel and install it in the add fuse along with a 10 amp fuse.Then install the add a fuse back in where you removed the fuse.Use the blue butt connector and splice the red controller wire into the butt connector.Another thing under the hood there are two fuses by the isolation module.One is a 15 amp which is for your park/turn and the other is 7.5 amp which is for you controller check those while you are at it.
     
    Last edited: Mar 11, 2012
  3. Nitrousguy

    Nitrousguy Junior Member
    Messages: 7

    Thanks for the welcome! Looking at the wires at the controller the standard red wire is connected to the fuse panel in an ignition slot. This wire does have an inline 10amp blade fuse in it. The second (FUBARed) wire is not fused and is connected to a constant slot in the fuse panel and is connected to a red wire with a yellow stripe that comes out of the controller. I checked all three fuses near the isolation module (one full size blade fuse and two mini blade fuses). I'm working on this today. I'll start tracing wires in an hour or so.
     
  4. chevyzrule810

    chevyzrule810 PlowSite.com Addict
    Messages: 1,238

    I would get rid of that second wire that shouldn't be there and see where they have spliced the power wire to.While you had your isolation module out of your truck did you try and put it in his truck for the heck of it to see what it did? Go to page 50 on this manual and see if it helps you out.The 4 port module has a 4th port for a longer headlamp harness.
    http://library.fisherplows.com/fisherplows/pdf/27179_070001.pdf
     
  5. Nitrousguy

    Nitrousguy Junior Member
    Messages: 7

    OK, I've solved the head light problem. The installer used those cheap blue quick splices. and if that wasn't bad enough they just squeezed the whole thing with a pair of pliers, it barely sliced the wire insulation. now I'm on to the hacked controller. I removed the extra lead wire and ran the red wire to the ignition ON side of the fuse box like it is supposed to be. I can't get the joystick box to turn on. I followed the red wire testing it at every connection and it runs through the firewall back to the isolator.My question is the wire that powers the joystick from the isolator is called swv-dc, it comes out of the middle of plug "B". What i need to know is what has to happen to trigger the isolator to send power out through that wire(swv-dc) back to the joystick?
     
  6. This might be too obvious but do you have the plow connected to the truck and the key on? Nothing will work without all 3 plugs connected to the plow.
     
  7. chevyzrule810

    chevyzrule810 PlowSite.com Addict
    Messages: 1,238

    ah motorman raises a good point that most miss.The plow must be hooked up to the truck in order to have the controller come on,so just turning the ignition on won't do anything unless the plow is hooked up to the truck.They do make butt connectors that have heat shrink already on them.All you have to do is crimp the wires inside,and give them alittle tug to make sure they won't come out,then hit the connector with a lighter and melt the heat shrink.
     
  8. Nitrousguy

    Nitrousguy Junior Member
    Messages: 7

    yes it's all connected and the ignition is on. The joystick never gets power. I think it's looking for power from the red w/yellow stripe. That wire looks like it's fed from that swv-dc wire out of the isolator. I need to find out if a ground is needed or what sends the signal to the isolator that tells it the plow is connected. On my trucks when the head lights are on, when you connect the plow the lights automatically switch over to plow lights even if the ignition is off. These work but only if the ignition is on. very strange.
     
  9. chevyzrule810

    chevyzrule810 PlowSite.com Addict
    Messages: 1,238

    get rid of that red/yellow wire if your truck doesn't have it then his shouldn't.
     
  10. Nitrousguy

    Nitrousguy Junior Member
    Messages: 7

    Chev...I did get rid of it. I have it hooked up exactly like my truck.. the way it should be. I was only stating that when it is hooked up the joystick works fine, but I know it's not right. that's why I'm trying to find the problem
     
  11. Nitrousguy

    Nitrousguy Junior Member
    Messages: 7

    Okay I fixed it! I found to problem to be a corroded wire in the Fisher factory sealed harness. It we right before the factory splice. It was completely green inside and the wire was double its original size. This wire fed the two mini fuses in the harness. I tested these fuses repeatedly. but I found that if the headlight are on these fuses somehow get feed power from the isolator. The best way to test for this is to remove the fuses and test which side of the fuse holder is getting power. I i had done that earlier it would have been an easier find. I have attached a schematic to show where the break was to help anyone who may have this problem in the future.

    Thanks to all that helped with this trouble shooting process!
     

    Attached Files:

  12. chevyzrule810

    chevyzrule810 PlowSite.com Addict
    Messages: 1,238

    so there are two additional fuses besides the park/turn fuse and controller fuse?