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No Low Beams

Discussion in 'Fisher Engineering Discussion' started by saber7, Dec 17, 2007.

  1. saber7

    saber7 Junior Member
    Messages: 21

    I have a 04 MM2 mounted on a 04 Avalanche all the lights work except the low beams , what should i be looking at/for?Do I need to have the isolation module tested?:help::help:
     
  2. gmcsierra1500

    gmcsierra1500 Senior Member
    from CT
    Messages: 150

    ...

    I had the same problem on my 2000 GMC sierra, id check and see if you have the right light harness the ones that go from your iso module to each headlamp on the truck, i had the wrong ones and thats what caused my problem
     
  3. saber7

    saber7 Junior Member
    Messages: 21

    Is anybody able to tell me what the part number should be for the lights on this vehicle?
     
  4. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    For the lights? Do you mean the light harness's for the plow light's?
     
  5. saber7

    saber7 Junior Member
    Messages: 21

    Yes I mean the light harness ,sorry my bad .The brain goes faster than the finger!!
     
  6. johnnard

    johnnard Junior Member
    from NH
    Messages: 10

    I had a Plymouth Road Runner once and BOTH low beams blew out at the same time. I chased wires for quite a while until my cousin suggested both bulbs were burnt out. He was right and I'll never forget it. Remember KISS
     
  7. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    For a 4 port Iso you should have:

    Short head light harness: 26351
    Long head light harness: 26352
    Light green Iso module: 27781

    Is this a new install or a swap off another truck? As you may need to change the configuration plug..
     
    Last edited: Dec 18, 2007
  8. saber7

    saber7 Junior Member
    Messages: 21

    this is swap off from a 04 Silverado (or so I was told). The DLR work so the low beam bulbs are o.k.Thanks B&B for your response.
     
  9. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Well if you not 100% sure what it was on before then that can definitely cause a problem...you might want to also check the configuration plug to be sure it's configured correctly....... make sure the pins aren't loose in the connector either....
     
  10. tkrepairs

    tkrepairs Senior Member
    from maine
    Messages: 186

    your avalanche with or without cladding? headlight setup is different, may be the problem....
     
  11. saber7

    saber7 Junior Member
    Messages: 21

    Without cladding , I tried the trick of flipping the plug on the low beam side and the lights work but very dim. I will cut,solder and shrink wrap them and see if that fixes it.Then plug the plugs together the proper way.
     
  12. sparky8370

    sparky8370 Senior Member
    Messages: 234

    Check the headlight fuses. Do both the high and low beam come on dim? That's what mine was doing. I had to swap the wiring around on mine too because the harness was for a neg common system. I kept checking my work over and over. It was the fuse. It blew when I had originally hooked them up with the wrong wiring. I didn't flip though, I changed the wiring around per a thread on here.
     
  13. saber7

    saber7 Junior Member
    Messages: 21

    it's just the low beams that are dim.
     
  14. smokefan20

    smokefan20 Junior Member
    Messages: 14

    i wonder if i have the same problem. my lights only work on high beams. i didnt hook up the light for the DRL's. its a 98 gmc k1500
     
  15. saber7

    saber7 Junior Member
    Messages: 21

    If your plugs fit togther try "flipping" them.
     
  16. saber7

    saber7 Junior Member
    Messages: 21

    just switched the wiring around and the lights are still dim,the parking light are as bright as the low beams
    Sparky which fuse do you refer to under the hood or dash???
     
  17. sparky8370

    sparky8370 Senior Member
    Messages: 234

    It was under the hood. When mine popped the headlights were on real dim. I assume it's some sort of safety feature so that if the fuse blows you have just enough light to pull over.
     
  18. sparky8370

    sparky8370 Senior Member
    Messages: 234

    I just went back and re-read this and have a questions for you.

    1.) Are you referring to the low beams on the plow or the truck?
    ---If you are referring to the plow lights, they are really dim, nearly useless actually. I
    adjusted the aim of them and that helped.

    ---If you are referring to the truck lights, that is the fuse problem I was talking about. If it
    is the truck lights you are referring to, than just disconnect the connections for the iso
    at the headlights, and hook them back up just like they come without a plow, and then
    see what happens and let us know.
     
  19. saber7

    saber7 Junior Member
    Messages: 21

    sparky, its the plow headlights only.
     
  20. sparky8370

    sparky8370 Senior Member
    Messages: 234

    Oh, well those are very dim anyway. Like way way dim. Like I said before, almost useless. Check the aim with your high beams. Then adjust them. I adjusted mine and it helped, but the low beams suck. It's a lot better now, but no where near where you'd think they'd be.