Trailer light problems

Discussion in 'Trucks and Trailers' started by gutpiles, Feb 9, 2008.

  1. gutpiles

    gutpiles LawnSite Member
    Messages: 38

    I went to hook up one of my trailers to do a estate cleanout yesterday and the regular lights & the brake lights work, but the 4 ways and blinkers do not. I am completely clueless when it comes to these things- is it the truck or the trailer and how can I fix it??
  2. SpruceLandscape

    SpruceLandscape LawnSite Senior Member
    from ohio
    Messages: 502

    double check that your turn signals on your truck are working before and after you hook up the trailer. If they are, then there is either a loose connection on the plug (I'm assuming its a 7-way plug?) or there is a short somewhere in the wiring on the trailer. If it is affecting both sides of the trailer equally then I would start by taking the connector apart on the trailer AND using a test light on the connector from the truck and make sure everything is together properly and you have juice coming from the truck side for your signals. If everything is OK there, start tracing the wires from front to back until you find a cut, crimp, or exposed area that might be the culprit. I would put my money that its at the connection area though.
  3. dgZtrak737

    dgZtrak737 LawnSite Member
    Messages: 120

    Thats odd your brake lights work but your blinkers dont. your right brake light and turn signal should one of one wire, your left brake and turn off the other. sounds like a fuse or relay on your truck to me, but Im curious to know what kinda truck you have
  4. DBL

    DBL LawnSite Silver Member
    Messages: 2,219

    check fuses first..then get a test light and go down the line starting at the truck
  5. Runner

    Runner LawnSite Fanatic
    Messages: 13,497

    Sounds like a bad ground on the trailer. Use a tester on the plug firs, and make sure you have signal(s) coming out your pigtail. After that, check your grounds on your plug to trailer, and then on your tail lights, check your wiring path to the front. Hope this helps!
  6. Landrus2

    Landrus2 LawnSite Fanatic
    Messages: 5,050

    Use this as a guide check your wire colors if they are not crossed.:drinkup:

  7. GravelyNut

    GravelyNut LawnSite Bronze Member
    Messages: 1,594

    I'd bet on the bad ground too. It does things that don't seem right. Just like this case. Check the bolts that mount the lights too.
  8. dgZtrak737

    dgZtrak737 LawnSite Member
    Messages: 120

    Thats sounds right too.
  9. SpruceLandscape

    SpruceLandscape LawnSite Senior Member
    from ohio
    Messages: 502

    I had a similar problem happen on a trailer that I had that was only 1 year old, started when I was pulling it in the rain one day. I did everything that people have suggested in the above posts, but with no results. I even went out and bought a new plug end for the trailer, but nothing worked. turns out that the moron that wired the trailer from the factory had pinched a wire that was right behind the light housing enough that it had worn thru the insulation and started to short when it got wet only. The short was enough to cause similar weird operation in that light only.
  10. CuttinUP

    CuttinUP LawnSite Senior Member
    Messages: 337

    Bad ground or maybe bulbs but i doubt it.

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