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wierd headlight issue

Discussion in 'Western Plows Discussion' started by fishinak, Nov 27, 2012.

  1. fishinak

    fishinak Junior Member
    from ak
    Messages: 11

    hello all. I have a Western Uni-mount on a 1999 GMC Sierra 6.0 L

    So last nite my headlights quit working on the plow. I unplugged the plow and the lights still do NOT work on the truck. but the hi beam indicator is ON on the dash and I can NOT take the brights indicator off. Turn signals and running lights are fine on both the plow and the truck.

    SO...I am thinking 1 of the 2 relays are bad. Because it seems like the truck "thinks" the plow is still hooked up, thus the I cant take the brights off.
    AND because beginning a few weeks ago the plow would not angle one way. After flipping the toggle around for 30 sec or so then it would randomly work fine (for awile).

    So what do ya think bad relays? If so do you know are these a generic relay I can find at NAPA or do I have to order a special Western relay?
    Thanks in advance for any and ALL help!
  2. nealybird

    nealybird Senior Member
    Messages: 750

    they don't need to be special relays, just 30-40 amp 5 terminal headlight relays.
    don't know if that's your problem though. maybe a funky grill connector?
  3. mishnick

    mishnick 2000 Club Member
    Messages: 2,353

    The lights and the angling issues are two different things. The relays only effect headlights. In fact I have installed some uni-mount plows where we just used the control harness and didn't hook up any headlight harness or relays at all and all the hydraulic function worked fine. I agree with nealybird on his hypothesis that your grill plug might be at fault for everything or perhaps relays for the lights and plug or broken wires causing the hydraulic function troubles.

    For spare relays I have just gone to the junk yard and robbed some old GM cars & trucks for their fuel pump and headlight relays. They have the same pinout and similar current ratings. I got about 500fuses and about a dozen 5 pin single plow double throw relays for $5 and an hour's picking time. If you want new Napa, Auto Pro, Auto Value all carry them and probably cheaper than your Western Dealer.
  4. fishinak

    fishinak Junior Member
    from ak
    Messages: 11

    Just bought new relays at napa and swapped them out. Same issue. I did not confirm that they were single plow double throw. But they were 5 pin. Is there a diff amongst 5 pin relays??
    Right now I am more concerned w headlights than blade angling.
    Wow the napa brand relays I just bought we're $20 each!
  5. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,392

    That's salty for relays. The plow relays have 87a in the middle
  6. mishnick

    mishnick 2000 Club Member
    Messages: 2,353

    If they have five pins and they fit then they will be single pole double throw. That is there will be two pins for in and out of the coil and then three more pins for the switch. One in and two possible outs.

    Single pole single throw will have only four pins.
  7. fishinak

    fishinak Junior Member
    from ak
    Messages: 11

    Yup just double checked #s on relays. They match. Guess that rules out the plow relays. Arrrrrgggg I'm frusterated!
  8. Drconstruction

    Drconstruction Junior Member
    Messages: 5

    I think you have the same problem I did. I spent 2 days pulling my hair out. My relays were right behind the drivers side headlight. There is a 3 prong plug thats comes from the headlight. The whole connector was corrroded, intermittent contact. I snipped them one at a time, and spliced them together, problem solved. I tried new relays, cleaned and greased every other electrical connection, and then I found that. I found a great wiring diagram, and schematic for the whole harness that shows that connector, and the relays. I laminated both of them, and I keep them in the toolbox with all the spare parts. I hope this does it for you. All that stuff was between the second battery and the headlight. Good luck.
  9. mishnick

    mishnick 2000 Club Member
    Messages: 2,353

    Since you have new relays and that didn't change anything you have to move on to two alternative possibilites, as above, check for corroded wires, and second you need to verify that everything is connected to the right place. Is it possible that you mixed something up? That's the thing I hate about the relays, there are so many connections that can be messed up. When I do a relay install / repair I like to replace the ends with female spades that have the catch on the bakc and then push them into relay sockets. These little socket link together and have a screw mount so you can secure them. Best part is that you can pull relays and replace them without risk of getting things mixed up.