1. Attention: We have put together a thread with tips and a tutorial video to help with using the new software. Please take a moment to check out the thread here: Trapshooters.com Tutorial & Help Video.
    Dismiss Notice

Utility trailer electrical prob..SOLUTION FOUND!!!

Discussion in 'Off Topic Threads' started by noknock1, Mar 18, 2012.

Thread Status:
Not open for further replies.
  1. noknock1

    noknock1 Active Member

    Joined:
    Jan 29, 1998
    Messages:
    1,399
    Location:
    Stranger in a Strange Land
    I inherited a small, single axle utility trailer which is the type with the flip down gate which acts as a ramp.

    When the lights are turned on the vehicle, all lights are on to the trailer, i.e., the side marker lights (four) and the rear tail lights. However, the passenger side trailer light is bright, like the brake light on.

    The passenger side light is obviously brighter than the driver side AND>>>> the truck BRAKE light, driver side faintly blinks. (opposite!!)

    When I turn on the right turn signal (passenger) the right trailer light blinks as well as very dimly the driver light on the trailer and the BRAKE light on my truck.

    If I brake, or just use running lights, or turn on the driver side, all is well.

    The plug that goes to the vehicle is the 4 prong style with an adapter that goes into the circle type for the my truck.

    Where do I start?

    Am I correct in assuming the 4 - prong plug is wired wrong which is causing bleed over?
     
  2. wireguy

    wireguy TS Member

    Joined:
    Jan 29, 1998
    Messages:
    3,715
    All your internet sites that deal with trailer sales will have a standard color code chart showing which wire colors are to be run to which lights. Don't forget there are two wiring systems, the Japanese (my word) system with separate amber turn signals and the American system in which the turn signals run through the brake lights. (or vice versa)

    Your situation sounds like it could be a bad ground. Make sure you have a VERY solid ground between the tow vehicle and trailer. That's the first thing I would check. I run a wire directly from the battery negative.
     
  3. BCJ

    BCJ TS Member

    Joined:
    Jul 29, 2010
    Messages:
    12
    Bad ground.
     
  4. X Trap 2

    X Trap 2 TS Member

    Joined:
    Jan 29, 1998
    Messages:
    1,125
    Check to see if that bulb on the passenger side is put in wrong.It may be 180ยบ off. One prong is down and one is up higher. I have seen it done. If it is a 1157 make sure the lead contacts are round and not diamond shaped. Ray
     
  5. JIM SIMS

    JIM SIMS Member

    Joined:
    Jan 28, 2008
    Messages:
    152
    Is tow vehicle japaneese ? If so an adapter
    sold at auto parts houses may be needed to isolate the circuits,
    and as WIREGUY stated you may have a ground problem.
    Jim
     
  6. Stl Flyn

    Stl Flyn Well-Known Member

    Joined:
    Apr 6, 2010
    Messages:
    8,737
    Spray WD-40 in the connectors. Plug and unplug the connections several times. Sometimes they get gunk built up inside the plug, and on the prongs. The circular plugs are used for electic brakes, etc. Usually the center prong is the ground. Look to see which prong has the white wire coming from behind the plug on your truck. Run a small blade screw driver, or knife in the slot of the prong to widen the prong, allowing for a solid connection, into your adaptor. If that don't work, if you have one, use a wire circuit tester. If you do not have a circuit tester, run a piece of wire from a bare metal area on the trailer to a bare metal area on your truck, and see if the lights work correctly. If so then reconnect, and clean the ground connections (White Wire) on both the vehicle and the trailer. The ground connections are usually exposed to water and salt if you are in a snow area, and corrode quickly. If it does not correct the problem, I would guess that it has something to do with the wiring shorting out on the trailer. The insulation may have worn off a wire and is powering the lights though the trailer frame. It may also be the circular plug receptcle wiring on your truck, don't match-up to the four prong adaptor. As stated above. There are two different kinds of circular to four prong adaptors, depending on if you have separate turn signals from your brake lights. You may have to get a circuit tester and go fishing. Good luck. Jon
     
  7. quartering

    quartering Active Member

    Joined:
    Mar 15, 2007
    Messages:
    1,440
    i've never inherited anything that wasn't a problem either
     
  8. noknock1

    noknock1 Active Member

    Joined:
    Jan 29, 1998
    Messages:
    1,399
    Location:
    Stranger in a Strange Land
    Thanks to everyone for the tips as I get some time this week after work I will take the advice. I am not seeing each light being grounded, however the one ground wire coming off the plug is definitely not a solid connection to the trailer as noticed it to be slightly corroded. I will snip that quarter inch and strip to start with a fresh ground wire. I pulled the ground wire off and when I reattached I did get a tiny, tiny, spark so I figured it was good. I will try that first.

    Yes it is a foreign vehicle, it is a GMC made in Canada... LOL although it has been a good one. I have had it for several years.

    I am not sure which round plug adapter I am using. I didn't realize there were two types. The driver side turn signal and brake light all blink with no separation between the blinker and the brake light.

    I have borrowed the trailer over the years and the lights worked fine. Based on the advice provided I am hoping that just that one ground wire has become corroded.

    The bulbs are the 1157 - two prong style so I will check to make sure it is not twisted the wrong way.
     
  9. Leo

    Leo Well-Known Member

    Joined:
    Jan 29, 1998
    Messages:
    3,051
    If it worked before it will work again. Grounds seem to always be a problem with trailers. When I wire trailers I run a seperate ground wire to each device, and always run the ground through the plug, not trusting a greasy/rusty trailer hitch to make a good connection. On the 4 pin connector White is chassis ground, brown is running lights, yellow is left turn signal and left brake, green is right turn signal and right brake. Good luck
     
  10. Recoil Sissy

    Recoil Sissy Well-Known Member

    Joined:
    Jan 29, 1998
    Messages:
    2,647
    On a related subject...

    A .22 caliber bore brush will clean up the female end of a corroded trailer plug quick.

    sissy
     
  11. Brian in Oregon

    Brian in Oregon Well-Known Member

    Joined:
    Jan 29, 1998
    Messages:
    25,254
    Location:
    Deplorable Bitter Clinger in Liberal La La Land
    Classic bad ground.

    What is happening is the electricity is flowing to the turn signal, but because the ground is bad, it skips the ground and backfeeds through the other element, which then lights up the other taillight.

    Remove the lights and reinstall after cleaning the mounting studs. Be sure to use star washers. These will cut through the paint and any rusty metal.
     
  12. noknock1

    noknock1 Active Member

    Joined:
    Jan 29, 1998
    Messages:
    1,399
    Location:
    Stranger in a Strange Land
    Thanks for the input. Got home too late tonight to try anything. Thanks for the advice.
     
  13. quartering

    quartering Active Member

    Joined:
    Mar 15, 2007
    Messages:
    1,440
    all of my trailer light problems have always originated at that weird, flat, four pronged rubber plug connection. i have a computer in my dashboard that i can talk to but i still have to connect my trailer lights to that thing. give me a break
     
  14. hfrogdogc

    hfrogdogc Member

    Joined:
    Jan 29, 1998
    Messages:
    173
    If you have a tilt trailer you have a problem on the ground. the only way I could get mine to work was to weld a small weld to the tongue an frame. a ground to the tongue only will not take care of your problem. this was on a new trailer from TSC. Henry
     
  15. noknock1

    noknock1 Active Member

    Joined:
    Jan 29, 1998
    Messages:
    1,399
    Location:
    Stranger in a Strange Land
    I finally got around to working on the trailer. I tested the lights after creating an extremely solid ground on the trailer and cleaning all connections. I ended up with the same problem and weird issues as previously mentioned.

    So as a last resort, which turns out should have been my first resort... LOL...

    I tried Ray's (X Trap 2) advice and sure enough the 1157 bulb was turned approximately 240 degrees. I took it out, replaced with half a turn and the lights work properly! I checked it on the explorer which has the four prong receptacle and the gmc with the round style adapter with no issues.

    I just wanted to give an update that a solution was found. Worst case scenario, maybe I have prevented any future electrical problems since I did clean up the ground anyways! Thanks again to everyone.
     
  16. halfmile

    halfmile Well-Known Member

    Joined:
    Jan 29, 1998
    Messages:
    15,648
    Location:
    Green Bay Wisconsin
    Guys, on the tilt trailer you need a jumper to carry the ground from the tongue to the frame.

    Couple spade lugs, and a foot of wire. About 40 cents.

    HM
     
  17. Haskins Bill

    Haskins Bill TS Member

    Joined:
    Nov 4, 2007
    Messages:
    777
    another related note: I had a seven pin connector on the truck that was corroded. Well after noticing an ad for a cartridge brass cleaning solution that said no ammonia so no brass loss, I used some househod ammonia and Q tips to clean the green gunk off the contacts and then sprayed some white lithium grease inside and no more problems!!!
     
Thread Status:
Not open for further replies.