1. Welcome to PlowSite. Notice a fresh look and new features? It’s now easier to share photos and videos, find popular topics fast, and enjoy expanded user profiles. If you have any questions, click HELP at the top or bottom of any page, or send an email to help@plowsite.com. We welcome your feedback.

    Dismiss Notice

Ultra mount on GMC no passenger side headlight

Discussion in 'Western Plows Discussion' started by kpmsnow, Dec 17, 2013.

  1. kpmsnow

    kpmsnow Senior Member
    from Elkhart
    Messages: 156

    Has worked fine but I noticed last night that it started turning on and off occasionally "just passenger side". Didn't seem to matter if I was in the act of plowing "lots of vibration" or just driving down the road, it would just occasionally shut off and turn itself back on. Then it finally just went out. High beam and low beam, neither work. HOWEVER when the headlight are in the off position and the daytime driving light come on it works just fine? The plow is a 4 port, and I tried a new wiring harness with no change. the truck is a 2008 GMC 2500 Hd. Any advise will be greatly appreciated!!!
  2. mishnick

    mishnick 2000 Club Member
    Messages: 2,353

    Since you have a four port iso module you can switch the two plugs coming from the truck headlights to the module. If you switch these temporarily it will indicate if the problem is on the truck or the plow. If the problem continues on the same side its in the plow wiring but if it moves to the other side it is in the truck. I expect the trouble is on the truck between the right headlight and the iso module.

    Have you tried disconnecting the plow? If so do the truck headlights work or go off like the plow? If they work then its either the plow again or the wire from iso module to grill.