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

One headlight ??

Discussion in 'Western Plows Discussion' started by caddytruck89, Dec 9, 2009.

  1. caddytruck89

    caddytruck89 Senior Member
    Messages: 157

    Quick one. Just finished an install on 04 gmc 3/4 ton. low beam on driver side is fine. Low beam on passenger is light very dim. I mean like a candle. Both high beams work great. Tried swapping bulbs no luck. Seems like a ground issue?? But why the high beams?? It's a 3 port isolation module. Ultra mount pro.
  2. Steve000

    Steve000 Junior Member
    Messages: 10

    I just installed the same plow/iso. mod. set up on a Ford Super duty and had a similar problem. The drivers side low beam wouldnt work on the truck or the plow but the high beams worked fine. The dealer i bought the wire harness from said some trucks may need a "configuration plug" which mine did. I plugged it in and the lights worked fine. The connector is located on the harness that plugs in to port 1 about 12" from the isolation module. If you cant get this plug i guess you could just splice the wires together depending on your set up. I dont know if this is the problem your having or not but hope it helps. Someone who knows more than me will likely chime in soon with a better response haha

  3. RepoMan207

    RepoMan207 PlowSite Fanatic
    from Maine
    Messages: 5,031

    The GM reverses it's positive / negitive common by reversing the headlight connector. Notice where the ISO Module's light harness plugs in to your actual trucks headlight harness. The connectors are labeled A & B, simply reverse the way they are plugged in and it will correct your problem. The Ford does this by the configuration plug.....to my understanding GM DOES NOT.
    Last edited: Dec 10, 2009