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Fisherxtreme V Lights & truck lights blink back & forth

Discussion in 'Fisher Engineering Discussion' started by todddude, Dec 18, 2014.

  1. todddude

    todddude Junior Member
    Messages: 16

    I have a 2007 Chevy 5500 with a xtreme V. The plow lights went out last week but still had running & blinkers. Check harness, fuses, plugs, pins & an area we repaired in truck wiring harness. Switched out module with another truck & switched out a new B & C harness. Now low beam truck lights & plow lights blink back & forth like a cop car! Running lights & blinkers still work. Put plow on another truck (matching setup) and it work fine. Put another plow on the blinking truck, same thing happens.

    Question is....is there a relay or item that I am missing to check? Looked at schematics but all looks good.

    I also checked a headlight repair (spliced wire) and re-soldered the repair just to be sure. Same thing sill happened. Isolate right side, unplug left and the right light works. Isolate left harness plug & nothing works.

    At a loss.....Oh, when plow is unplugged everything on truck works fine.
     
  2. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,005

    Ck the gnd from the plow plug, throughout the system.
     
  3. todddude

    todddude Junior Member
    Messages: 16

    Yea, the grounds were the first thing I checked. Beginning to think it may be a relay within the truck itself since it does it with each plow we hook to it. I hate frustrating simple problems!
     
  4. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,005

    How can it?
    The main gnd and the small gnd on the plow are what switch the trk and plow lights through the iso module.
    I'd start wiggling wires
     
  5. todddude

    todddude Junior Member
    Messages: 16

    Yea that is what I said!!! We have replaced each A B & C harness, reattached the grounds and the only thing that we found odd is when we unplug the driver side it causes the passenger side to switch up. It may be isolated to the truck headlamp or the truck harness. It is the oddest thing. The new harnesses stopped the blinking back & forth but not getting all the lights switching correctly is still eluding us. We are swapping out a few relays from another 5500 I have just to remove that as a possible thing. I guess the daytime running light relay can cause issues if it isn't working properly.
    Next stop the professionals on Monday! I will keep you posted!:mechanic: