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no high beams on truck

Discussion in 'Truck & Equipment Repair' started by Eboucher, Feb 9, 2016.

  1. Eboucher

    Eboucher Junior Member
    Messages: 25

    Hi all, i have a unique issue...

    after plowing this weekend all was well, i dropped the blade after the storm and went on my merry way. tonight i went to turn on my high beams and i have nothing. low beams work fine. when i got home i plugged the plow back in and i have high and low beams. i swapped relays and both high and low relays are good. i have not yet bypassed the isolation module to isolate the issue, but any ideas?

    im running a 2005 GMC Sierra 2500hd, has the factory plow prep package, 4 port isolation module.

    everything was running good up until this past storm.

    any input would be appreciated.
  2. Eboucher

    Eboucher Junior Member
    Messages: 25

    also want to add, i had lost the ground on the solenoids yesterday. the three were daisy-chained together but the wire broke where it connected to the harness. is it possible it tired to ground out through the lighting harness?


    checked the two fuses and the fuses in the harness are good,
    you can hear the high beam relay click when you turn it on, but no light...
    i have also swapped the high and low beams at the bulbs to make sure by some freak issue both bulbs died.
    Last edited: Feb 9, 2016
  3. Randall Ave

    Randall Ave PlowSite Veteran
    Messages: 3,581

    Ask the mod to move this to the Western thread. You will get more responses.
  4. Eboucher

    Eboucher Junior Member
    Messages: 25

    are the western and fisher modules the same?

    i guess i forgot to add its a fisher MM2 4 port module..