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Using an 08 silverado plow harness on an 02 Silverado and no low beams???

Discussion in 'Western Plows Discussion' started by mossman381, Nov 30, 2011.

  1. mossman381

    mossman381 2000 Club Member
    Messages: 2,410

    Ok this is what I did. I used the 3 port iso plow harness that I had on my 08 silverado HD and put it in my 02 silverado HD. Everything works great except the low beams. I had to cut the low beam plug off the original harness because the 08 had a different bulb. All I did saw swap out the plug on the plow harness for the plug that plugged into the light on the truck. When the plow is not hooked up the low and high beams work fine. When I plug the plow in I only have high beams. But when I hit the high beam switch as it goes from high to low beam the lows come on for a split second. So I know they are getting power. On the 08 the low beams stayed on with the high beams, but the plow has one bulb so it was either high or lows were on. I have looked and thought and can not figure it out. I do have an older uni-mount that I converted to the 3 plug with the nighhawk lights. Anybody have any ideas? :confused:
     
  2. basher

    basher PlowSite Fanatic
    from 19707
    Messages: 8,992

    The unit you took it off of had high side switch system, the unit you transfered it to had a Low side switched system. a simple set of adapters will solve that problem.
     
  3. mossman381

    mossman381 2000 Club Member
    Messages: 2,410

    Do you have a part number? Where would this adaptor go? Also the daytime running lights will not come on with the plow plugged in. I know on the 08 they used the low beams as the running light at lower voltage.
     
  4. mossman381

    mossman381 2000 Club Member
    Messages: 2,410

    It looks like the only difference in hooking up a newer plow onto an 08 and an 02 is the light harness. If I get the 29048 harness will that fix the problem? Is ther any way to get the harness that I have to work?
     
  5. tractorbill

    tractorbill Member
    Messages: 65

    check the orientation of the light plugs the orange wire on the truck should go to the common on the plow harness.
     
  6. mossman381

    mossman381 2000 Club Member
    Messages: 2,410

    That was the first thing I checked. I think the wires are all hooked up right. The only difference in the 08 and the 02 seems to be the low beam bulbs. Why would that cause a problem?
     
  7. tractorbill

    tractorbill Member
    Messages: 65

    The 02 truck has a positive common setup and the 08 has neg. Did you change the configuartion plug?
     
  8. mossman381

    mossman381 2000 Club Member
    Messages: 2,410

    What is the configuration plug? If I convert the truck so the low beams stay on with the high beams would that trick the plow lights into working?
     
  9. basher

    basher PlowSite Fanatic
    from 19707
    Messages: 8,992

    As I said; a set of adapters will fix the problem.
     
  10. mossman381

    mossman381 2000 Club Member
    Messages: 2,410

    I grounded out the low beams so they stay on with the high beams on the truck. But the low beams on the plow still won't come on by themselves. Now the lows are on with the high beams on the plow. But when I switch over to just lows they turn off. Will that burn up the bulb running both high and lows at the same time? Any body have any ideas on how to get the lows to work. At $190 to get the 29048 harness, I am looking for a way to get this harness to work. There has got to be a way.
     
  11. tractorbill

    tractorbill Member
    Messages: 65

    Sorry work on 3 and 4 port all day long, no config plug on 3 port it should be blank is it? The iso module works on imput and output. Are you SURE about the oriention of the plugs? Do you have the adapter plugged in with the 2 relays on it (28027)? The B and C harness's are all basically the same except the plugs so you should be able to do this.
     
  12. mossman381

    mossman381 2000 Club Member
    Messages: 2,410

    I appreciate the help. The orange wires on the headlights are connected to the common wire on the plow harness. Checked and rechecked. There is a 3 prong plug that has nothing plugged into it. But nothing plugged into it on the 08 either. I will check for the 28027.

    Playing around with it I found that if I unplugged the high beam on the drivers side the low beams worked on the passenger side. But when I unplugged the passenger side high beam none of the lights would work. It is like the high beams are feeding the low beams and not letting the low beams work right. Is there a wiring diagram somewhere?
     
  13. tractorbill

    tractorbill Member
    Messages: 65

    Go to westernplows.com parts and service tab,then Quick search, put in electrical schematics isolation module. It should give you the whole manual. Then go to 3 port and 3 plug straight blade. Ck the imput from the truck to the module first when you start . Good luck Bill
     
  14. Philbilly2

    Philbilly2 2000 Club Member
    Messages: 2,609

    sounds like you need to make the harness negitive common.

    You will do this by taking the plug that connects to the back of your headlight unplug it from the headlight, and their should be a blud clup that holds the two wires into the plug. remove the blue clup, pull the wires out and switch the wires in the plug. This will change it to from positve common to negitive common or vice versa. Do this to the oppisite side of the harness and all should work.