1. Welcome to PlowSite. Notice a fresh look and new features? It’s now easier to share photos and videos, find popular topics fast, and enjoy expanded user profiles. If you have any questions, click HELP at the top or bottom of any page, or send an email to help@plowsite.com. We welcome your feedback.

    Dismiss Notice

8.6 mvp ultra mount headlight question

Discussion in 'Western Plows Discussion' started by probee, Oct 3, 2010.

  1. probee

    probee Member
    Messages: 37

    I have a 08 gmc 2500hd, ultamount 8.6 mvp....I blew a headlight on the passenger side on the truck...replaced the bulb still no power to bulb....I unplugged the socket and plugged in the factory socket and the light works....my question is...could the 3 port module be bad or could it be in the harness? Thanks for your input!
     
  2. Western1

    Western1 Senior Member
    from MI.
    Messages: 676

    Could be either. Try switching the harnesses.
     
  3. probee

    probee Member
    Messages: 37

    Not to sure what you mean....replace the harness or can I try to plug into a different port and see if that works. Thanks
     
  4. Western1

    Western1 Senior Member
    from MI.
    Messages: 676

    Sorry,if it's a four port you can try swapping the 3&4 harness. Still might be able to try with the 3 port by swapping pass side and drivers. Do you know anyone else with the same setup? If you do you can try parts of his?
     
  5. no lead

    no lead PlowSite.com Addict
    Messages: 1,308

    i'm thinking bad connection. you said blew a light. sounds like it lost ground somewhere. put the old bulb in the other light. if it works you have harness or connection issues. unplug the light adaptors and look at the pins. any green means trouble. if they look good grease them and hook back up. then check for power and ground at the plow light socket.
     
  6. probee

    probee Member
    Messages: 37

    I have no power at the plowlight socket...so just using factory socket..the pins in the harness all look good,not to sure what you mean about the old bulb,the old bulb blew on the passenger low beam,replaced it with a new bulb and it does not work...I have no power on passenger side light harness.do you think a bad ground would make the bulb blow?Can i switch ports to check for lights? Thanks for your help!
     
  7. no lead

    no lead PlowSite.com Addict
    Messages: 1,308

    if you took out 1 bulb and the new on doesn't work either its not the bulb.:whistling::whistling:
     
  8. probee

    probee Member
    Messages: 37

    Your right! but the original bulb did blow and then i now have no pwer at the end of the light harness...sorry for being a little confusing,,i will check all the grounds and connections tomorrow...thanks
     
  9. Chipper

    Chipper Member
    Messages: 78

    My F-350 has separate fuses for each H/L. If you blew the bulb it would likely take out the fuse. Not sure if its the same on Government Motors. Also it could be a bad ground. Had to chase that on my MVP and it turned out to be a bad contact. Just bent the contact and its been fine. I thought it HAD to be the module but dealer tracked down the bad ground.
     
  10. no lead

    no lead PlowSite.com Addict
    Messages: 1,308

    i think i have seen 2 modules that were defective since they started using them. your truck has independant fuses also.
     
  11. probee

    probee Member
    Messages: 37

    Yes ,I checked both fuses and they were good...today i swithched ports on the harness to see if the light would work on the other port and it did...not to sure but it sounds to me like that one port could have gone bad?
     
  12. Chipper

    Chipper Member
    Messages: 78

    Sounds exactly like the problem I had with mine. One of the pins in the plug for the H/L's wasn't making good contact. This was for the ground. The western plow dealer switched out the module with a new one and same problem. He tested the wiring and found out it wasn't making contact on that one pin, no continuity for that circuit. NO it wasn't dirty or corroded, new plow and wiring. All we did was bend the contact in the plug so it made contact and problem solved. Must have gotten bent slightly, somehow while plugging and unplugging the H/L????
    Hope this helps with your problem.