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Hi beam works...Low beam doesnt

Discussion in 'Western Plows Discussion' started by Sno Biz, Nov 23, 2008.

  1. Sno Biz

    Sno Biz Member
    from Chicago
    Messages: 55

    Can this problem be a relay or coincidence that both low beams are burnt? Anyone else ever had this happen? If it is the relay, where is it located, under the hood or under the dash?

    Thanks, jR
     
  2. Dstosh

    Dstosh Senior Member
    Messages: 534

    Mine were under the hood. They should be by the drivers side headlight. What kind of vechicle are you using? I am having the same problem, but it is in both my truck and plow.
     
  3. Sno Biz

    Sno Biz Member
    from Chicago
    Messages: 55

    Its a 94 GMC Sierra 1500 with a 7 1/2' Western Unimount
     
  4. Dstosh

    Dstosh Senior Member
    Messages: 534

    Ah I dont know much about gm's. But the realys should be up by the head lights. They are available at napa. Just take your old one in. Do your low beams work when the plow isnt hooked up?
     
  5. sechracer

    sechracer Senior Member
    Messages: 478

    try swapping the two relays first..... that will tell you if it is a bad relay... Usually on the passenger side near the headlight is where you will find them.
     
  6. Dodge Plow Pwr

    Dodge Plow Pwr Senior Member
    Messages: 568

    I had the same problem last year. It was a bad relay cube. It looks fine, but inside it someplace there was a problem. Put a new one in and it worked like new. As far as locations, I find no one person puts things in the same place regardless. Good luck
     
  7. Sno Biz

    Sno Biz Member
    from Chicago
    Messages: 55

    Found it! Had to pull the grill off to access it behind the driver side headlights. The installer had the relays protected by a heavy plastic bag. I switch them both since I had them out. Works as good as new.
    Thanks for the help.
     
  8. ergsr

    ergsr Junior Member
    from NH
    Messages: 2

    I have a similar problem, about 2 months ago, my low beams stopped working on the truck without the plow on. I changed the low beam relay and it was fine for a few weeks. With the plow on, the plow high and lowbeams work. Then it happened again, this time I bypassed the plow harness and hooked it up back to the GM headlight plugs and have not had any issues. This past weekend, I replaced the low beam relay with a brand new relay and added the hardness back in and it still does not work. I'm not sure if I should replace the harness or I have another issue, it seems the culprit is the low beam on the harness. I have a MM1 on a 2001 Chevy Silverado, its a 6 relay harness. Any recommendation would be greatly appreciated. BTW this is not a new installation, I have had it installed since 2001. Thanks, Eric
     
    Last edited: Dec 8, 2008
  9. Crash935

    Crash935 2000 Club Member
    Messages: 2,377

    There are 2 low beam relays in that harness, one for the truck low beams and one for the plow low beams. Did you replace the right one?
     
  10. ergsr

    ergsr Junior Member
    from NH
    Messages: 2

    I only replaced the truck rely, maybe I should replace the plow relay too. I have the wiring schematic and that is what I'm following. I figured the plow lights works it must be the truck side. Over the weekend when I hooked up the plow harness with the new relay, it still didn't work. I was going to trace the line tonight and see if I can find a break in the line
     
  11. got-h2o

    got-h2o 2000 Club Member
    Messages: 2,439

    This will also happen if your low beam tab breaks off in the plowside harness. They'll corrode and disappear sometimes, and for some reason, the low beam one is the most common. Problem sounds like a relay b/c it was intermediate, but just an FYI about the tab. Replacement splice in plow side harnesses are available and about $40.
     
  12. Crash935

    Crash935 2000 Club Member
    Messages: 2,377

    Check to make sure that you have power on the brown wire at the relay with the lights on.