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Tundra Trailer Lights Not Working

Discussion in 'Towing & Hauling' started by avxflyer, Aug 13, 2019.

  1. Aug 13, 2019 at 2:48 PM
    #1
    avxflyer

    avxflyer [OP] New Member

    Joined:
    Aug 31, 2016
    Member:
    #4394
    Messages:
    4
    I've got a 2011 Double Cab 4x4. Having a saltwater boat and trailer, lights have always been a bit of a problem. I converted to LED a while back and this season noticed that my running lights and left turn signal/brake lights were not working. Finally got around to troubleshooting and the trailer seemed fine. Tested output at the truck and those pins in the 5-pin adapter were not working. Saw another thread on here about the harness being bad, small wires and such, so went to work trying to find the answer. I pulled the harness and checked the output from the square plug where the harness plugs in. All working there. I started to disassemble the harness and found a design defect that causes the problem. The harness makes an almost 90 degree bend to the plug receptacle attached to the truck. The harness has a locking point on only one side of the plug. This allows the opposite side to move enough to allow the pins to lose contact with the receptacle. If it moves too much, the pins will come out and bend away from the harness and then you have no lights or left turn signal. You can see the bent pins in my case in the round plug. Hope this helps the next person troubleshooting the problem.

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  2. Dec 24, 2019 at 10:29 AM
    #2
    Crews44

    Crews44 New Member

    Joined:
    Jun 25, 2017
    Member:
    #8262
    Messages:
    76
    Gender:
    Male
    First Name:
    Steve
    Southern NJ
    Vehicle:
    2014 TRD Limited Crew Max
    Thanks for this tip. That was my problem of my trailer running lights. Took bumper off to POR15 and paint hitch and the large 90 deg plug was not connected correctly and bent the pin for running lights.
     

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