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Headlights wigging out . . .

Discussion in 'Western Plows Discussion' started by BGehl, Jan 22, 2011.

  1. BGehl

    BGehl Member
    Messages: 89

    Hey guys,

    I have a unimount on a 99 f250, yesterday as i was plowing during daylight i realized my headlights on the plow were out and the truck lights were on.

    I checked my plow/truck connections and every thing seemed ok. It was all the lights: parking, directional, and headlights, and high and low beams did not matter. The plow still worked fine as far and movement and control goes.

    I went on plowing and right around dusk they started flicking back forth between truck and plow. This happened as i was plowing and as i transported the plow from drive to drive (so it not like it was only doing it when the plow was all the way up or only to one side). Finally they stayed on the plow and was fine for the rest of the night.

    I just replaced the headlights and the relays at the beginning of this year. Anyone have a guess as to what was happening? Anything i should check to nip this in the bud, in case it is coming back?
     
    Last edited: Jan 22, 2011
  2. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    As I recall this system has a common ground for all the lights that goes to the motor negative. If this wire is corroded all the lights will go out. That is the case right? When the headlamps go out the markers and signals fail too? Is your controller reacting in any way? On late model Westerns it is the presence of the headlamps (pluged in) that tells the relays / isolation module to switch to the plow. The fact that your truck lights come on indicates that the relays are switching but you didn't complain about the plow shutting off. That is odd. Still the only thing that can kill all the lights is that common ground. Even when the relays switch to the truck the markers and signals on the plow should work because they are connected in parallel. Markers and signals do NOT have anything to do with the relays so again that points to a common ground connection but it can't be in the heavy pump motor ground or the plow would be failing too. It must be a problem on the plow.
     
  3. BGehl

    BGehl Member
    Messages: 89

    Yes all the lights fail and the controller is fine. But i am not sure if i follow all the details of your post . . . .

    Are you suggesting i check the common ground for corrosion, and where would that most likely be?

    Or should i be checking the wiring somewhere on the plow itself?

    When i left this morning everything was fine but when i came home this afternoon, it had switched back to the truck again.
     
  4. BGehl

    BGehl Member
    Messages: 89

    I just checked where the orange and black wire is bolted to the plow motor, it seems fire. i didnt see any sign of corrosion. Where the wires jump off the truck battery there was a little corrosion but nothing real bad.

    Any one have any guesses?
     
  5. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    If all the lights on the plow are failing then yes it is probably a ground failure on the plow itself. If the vehicle side ground was failing then the pump motor wouldn't work but it does. Maybe try opening one of the headlamp assemblies on the plow and jumping the ground directly to the battery negative post. When you look at the marker / signal lamp you should be able to see which is ground. I can't remember the colour but if you can figure that out then take a jumper and connect it from that ground to the battery ground. If that makes the plow lights come on then there is a break somewhere between there and the pump motor. Trace the cables and look for damage.
     
  6. twinman326

    twinman326 PlowSite.com Addict
    Messages: 1,683

    Check the "brown " wire on the driver side parking light to make sure it is connected properly and not corrode. This wire activates the relays to switch over from truck to plow lights.

    check the black/orange wire. This wire is the ground wire..Make sure the wire is clean and secure.

    I know you mention you check the connector. Re-check the plug connector and make sure it is clean and has dielectric grease.
     
  7. BGehl

    BGehl Member
    Messages: 89

    thanks for the help. i'll check both of these over again tomorrow.

    twinman: the brown wire on the driver side parking light: is that on the plow light or the trucks light? I assume truck, right?
     
  8. hondarider203

    hondarider203 Member
    Messages: 38

    dont mean to stell your fourm but i am having the same problem but my markers and turn signals work i replaced all the conections and a couple of my relays and now i have no head lights at all unless i unplug the plow. my dealer said that i should only have two relays but i have 6 can enyone tell me what the other 4 might be for?? i ordered a new truck side harness and new plow side pig tail and all new relays. im lost and need some help
     
  9. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    If your vehicle only requires two relays and it has six then it may have been modified or the wrong harness butchered in to make it work. I would wait for the new harness, it should come with a schematic and instructions. Install the right one and hope that it works.

    What I often do with older "relay" plows with electrical problems is retrofit them to 3 port isolation modules and eliminate the relays all together. If your Western dealer is worth his salt they will be able to order exactly what you need but it can cost a bit.
     
  10. BGehl

    BGehl Member
    Messages: 89

    mishnick: you were right, the brown wire had a good deal of corrosion. If fact by the time is followed it it had rotted right away completely and was just dangling. now i have to figure out where it should go. . . . What should it be connected to? Is it right on the headlight or does it go to somewhere else?
     
  11. twinman326

    twinman326 PlowSite.com Addict
    Messages: 1,683

    BGehl

    You assume right, on the truck.

    Oh I was right.

    Brown wire to the "parking light" on the driver side (truck)

    The brown wire activates the relays to switch from truck to plow. When you switch on the headlights, the parking lamps tell the brown wire to power the relays...When you repair it the wire using a bullet connector, I would put some dielectric grease on it also..
     
    Last edited: Jan 23, 2011
  12. twinman326

    twinman326 PlowSite.com Addict
    Messages: 1,683

    hondarider203

    what kind of truck do you have (year, make, model), and what kind of headlights?
     
  13. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    The headlamp assembly ground usually comes from inside the headlamp housings. Sometimes the marker, signal and headlight ground are collected together at a rivet in the lamp housing and then bridged down to the motor negative. In this case I would suggest ordering a new harness because it is difficult to repair effectively. I don't expect this is an espensive harness, well worth a few bucks to have an original cable with no jerry rigged connections.
     
  14. twinman326

    twinman326 PlowSite.com Addict
    Messages: 1,683

    BGehl

    Did you fix your problem?

    If you believe the ground wire (black/orange) is bad inside the headlamp (plow side), just run a single wire from the housing to the ground wire on the plow frame..Or just go out and buy the "repair" ends..Much cheaper the buying a whole harness..On the other hand, if you had a ground problem in the harness itself, nothing would work on the plow side.

    plow
    9pin.jpg

    truck
    9pin truck.jpg

    9pin.jpg

    9pin truck.jpg
     
    Last edited: Jan 23, 2011
  15. twinman326

    twinman326 PlowSite.com Addict
    Messages: 1,683

    BGehl

    You in Elmira??
     
  16. hondarider203

    hondarider203 Member
    Messages: 38

    it is a 2001 chevy 2500 hd
     
  17. hondarider203

    hondarider203 Member
    Messages: 38

    not shure what kind of lights though
     
  18. twinman326

    twinman326 PlowSite.com Addict
    Messages: 1,683

    hondarider203

    Unimount plow, or Ultra?
     
  19. hondarider203

    hondarider203 Member
    Messages: 38

    unimount it has a 9 pin harness
     
  20. twinman326

    twinman326 PlowSite.com Addict
    Messages: 1,683

    hondarider203
    If you do have a unimount, the schematic shows 6 relays


    2001chevy relays.jpg

    Start from here

    Check your wires on the relays to make sure there are in the correct place. Also check the fuse. Check the brown wire (vehicle relays pin #85) to make sure it is connected into the vehicle harness and not corrode.

    Here is the link to the pdf file. look on pg#14
    http://library.westernplows.com/westernplows/pdf/63357_103103.pdf

    2001chevy relays.jpg