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Ultramount blowing truck side fuses

Discussion in 'Western Plows Discussion' started by JCI Trans, Jan 3, 2010.

  1. JCI Trans

    JCI Trans Senior Member
    Messages: 313

    I have an '04 3 plug ultramount with a 4 port isolation module. The last 2 storms i keep blowing the truck side front parking lamp fuse. I replace it when the plow is removed and it does not blow again until i reconnect the plow. (sometimes it wont blow until a couple hours into the storm). The truck has automatic headlights, and i have noticed that when i start the truck at night the vehicle headlights turn on when i crank the truck, then before i release the key the plow lights kick on. In the past the plow lights always came on right away, as they are supposed to. Could the isolation module be bad? I have checked the parking lap connections and they all seem tight. Thanks in advance!
  2. no lead

    no lead PlowSite.com Addict
    Messages: 1,308

    did you check inside the light buckets on the plow for a shorted wire? is the plow side harness factory or has it been repaired?
  3. kmac

    kmac Member
    Messages: 30

    If truck lights come on first then plow lights, the relay is probably sticking. That should not blow a fuse. Sounds like a short.
  4. JCI Trans

    JCI Trans Senior Member
    Messages: 313

    I will check the headlights for shorts when im at the shop tomorrow. It is an Isolation module system, so no relays to check/replace. Has anyone ever had to change their isolation module? If so, what was the cause?
  5. JCI Trans

    JCI Trans Senior Member
    Messages: 313

    It is the original wiring, with no repairs anywhere in the line. I took apart the headlights and found some rust in one of the parking lamp bulb sockets. I cleaned it out, sprayed QD and reinstalled new bulbs with dielectric grease. I had the plow on for 2 days with no problem. I took the plow off to move a trailer so i could put the plow away, when i reconnected the blade to put it away, it blew in the 3 minutes it took to move it. I know everyones' favorite problem is an intermittent electrical problem :gunsfiring::gunsfiring:. Looks like i'll remove the harness on both sides and reinstall with new wire connections.
  6. fabcraftinc

    fabcraftinc Member
    Messages: 69

    I would pay close attention to the connection on the truck where the parking lights were tapped into. Look for corrosion and any bare wire.
  7. JCI Trans

    JCI Trans Senior Member
    Messages: 313

    I cut back the wires and made new connections at all the parking lamps, one was questionable, the rest looked ok. I used uninsulated crimp connectors and heat shrink tubing, so they should be sealed pretty tight.