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B&B- need help ith unimount harness

Discussion in 'Western Plows Discussion' started by Philbilly2, Nov 11, 2007.

  1. Philbilly2

    Philbilly2 2000 Club Member
    Messages: 2,567

    If anyone can help me, I am working on truck right now that I got the unimount harness on the truck. Controls the plow fine. Up, down and angles fine.

    My problem is that I cannot got the headlights to switch over from truck to plow:

    DRL's power the headlights and parking lights on the plow. so I don't think it is the plug-in.
    Turn on the parking, low beams, and the high beams the truck lights stay on.
    I checked all the relays and if I run a 12v power directly to the coil, lights work.
    When you flip the switch in the cab, truck lights stay on and no plow lights come on.

    I checked the wiring to the relays and it all seems to be correct. Couldn't tell you for sure because my printer doesn't work so I had to run inside, look at the computer screen and then run out and check.

    By the way, the checked the plow lights, they work fine on my truck so I know it is in the harness.

    The truck that I am working on is a 2002 Chevy 2500HD.
     
  2. Mark13

    Mark13 PlowSite Fanatic
    Messages: 5,734

    You sound like me right now. 3 days of messing with my plow lights and they still don't work right. Btw, are you supposed to have a switch in the cab to choose either truck or plow lights or should it do it automatically when you plug in the plow hookups to the grill connectors?
     
  3. nobletousha13

    nobletousha13 Senior Member
    from VA
    Messages: 124

  4. 6feetdeep

    6feetdeep Senior Member
    Messages: 141

    Sounds too familiar! I just walked in from the garage, I was trying to get the unimount harness figured out on my '99 chevy. :dizzy: That link to the western instructions couldn't have come at a better time, thanks! :waving: The harness I got with the plow I bought had a lot of corrosion into it:cry: , and I am lengthening all the leads, so I can put the relays back by the firewall, and more protected from the elements.
     
  5. Mark13

    Mark13 PlowSite Fanatic
    Messages: 5,734

    We should start a group- Chevy Unimount Owners with Light Problems.

    I'll be member #1 :D

    My 98 is driving me and my dad nuts with these stupid lights. Heck with it, I'll just plow during the day.
     
  6. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Philbilly are you positive you have the correct headlight plug in harness for the 99-02 neg to excite headlights? The number on the harness should be: 26071 Even though your DRL's work doesn't mean the rest of the wiring is correct as the DRL's on the '99-up Silverado's is totally seperate from the regular headlights..... lemme know.


    Do the plow light relays click when you turn on the lights?
     
    Last edited: Nov 11, 2007
  7. Philbilly2

    Philbilly2 2000 Club Member
    Messages: 2,567

    Plow lights should jump when you plug in plow...no extra switch in cab.

    Yep, that's what I had. My wife told me she can transfer it to her laptop and I can take that out to the shop with me. I'm gunna try that next.

    No...nothing, only thing that works is turn signals, and DRL's nothing else even click's a relay.

    Thanks guys.
     
  8. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    OK, check the harness # and do a little "test light diagnosis" and keep us posted..

    Does the harness have the extra DRL module/wiring with it? p/n 26078
     
  9. 6feetdeep

    6feetdeep Senior Member
    Messages: 141

    I'm member #2. Bang head here: X :realmad:
     
  10. OneBadDodge06

    OneBadDodge06 Senior Member
    from Iowa
    Messages: 734

    I really think B&B is right here.....I had the same type of symptoms when I tried to use my 04 harness on my 02. Power to everything, it even clicks, but nothing to the headlights.
     
  11. Philbilly2

    Philbilly2 2000 Club Member
    Messages: 2,567

    Alright, where do I find a part number. The only part number that I can find is on the replacement fuse there is a part number for that....any suguestions?
     
  12. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Should have a white tag on it somewhere...if it's still there..:realmad: The only other way to identify it is to check every single wire and pin to see if it matches the colors and locations in the diagram...kinda like wiring in reverse..
     
    Last edited: Nov 12, 2007
  13. nobletousha13

    nobletousha13 Senior Member
    from VA
    Messages: 124

    parking lights

    you said your turn signal works, but do your park lights work.
     
  14. Philbilly2

    Philbilly2 2000 Club Member
    Messages: 2,567

    Yeah, that is what I though, I got the diagram on the movable computer no so I am going to take it out and try to see if they all match, but from what I remeber from Sunday, they are all the same colors to the same pins.

    Nope, just trun signals:dizzy: Turn signals on plow and truck, Parking lights on only the truck
     
  15. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    If the parking lights don't work then neither will the plow lights as the head light relays are tripped by turning on the truck parking lights. Check your brown wires at the relays with the parking lights on with a test light. If the brown doesn't have power then the relays won't switch. Are you sure you connected the parking light wire to the correct wire on the truck?
     
  16. Mark13

    Mark13 PlowSite Fanatic
    Messages: 5,734

    If we combined what we have working I think most of my problems besides the headlights would be fixed. I had running lights on my truck and plow but not a passengers side directional on the plow.
     
  17. Philbilly2

    Philbilly2 2000 Club Member
    Messages: 2,567

    Hey B,

    If I take power directly from the battery and power up the relay to the 86 on a typical relay, that sould be the (+) connection. If I power that and the lights come on, that is a way to test the coil... right. Does that mean the relay is good?

    And thank you for that idea, I'll check the browns. Your sayin that if the parking lamps relay doesn't get power, the headlights will not work.


    I'm smellin what you stepped in Mark. :dizzy:
     
  18. sechracer

    sechracer Senior Member
    Messages: 478

    Mark, Do you have the parking lights on both sides of the plow? or just the right side?. If you do have them on both sides, then your directional problem is most likely a bad connection at the point you spliced in. How did you connect it? Soldered in? or did you use one of those plastic clips that make it so you dont have to cut the wire?
     
  19. Mark13

    Mark13 PlowSite Fanatic
    Messages: 5,734

    I have marker lights on my truck and plow. We used those little plastic smash clips and iirc we tested those and they were getting power. I guess its worth another shot. Also there is a purple wire on the passengers side and two purple wires on the drives side behind the truck lights, what do those do? We hooked the drivers side two together and nothing changed.
     
  20. sechracer

    sechracer Senior Member
    Messages: 478

    you have 2 purple wires? Do you have the brown and grey ones too? On the drivers side, there should be a grey wire behind the lights. That wire taps into the Drivers turn signal. If both wires are purple, I would trace them back to the harness and see if someone cut the wires and spliced 2 purple ones in. If someone did hack the harness, then that is probably what they did. Brown would go to the parking lights. I would unhook the 2 purple and hook them up one at a time and see which one makes the park lights work, then hook the other into the turn signal wire.
    If you have park lights on both sides of the plow, odds are its not ground because they share it with the turn signals. As for your headlights. I need to go find your post on that one because I cant remember exactly what you said. Good luck.

    Tom