Yet another trailer wiring question

Discussion in 'Wiring' started by long_tall_texan, Nov 5, 2017.

  1. long_tall_texan

    long_tall_texan New Member

    5
    0
    Oct 21, 2017
    DFW Metro
    2002 Coleman Utah and none of the exterior trailer lights work (clearance, brake, turn signals). Wires at the tongue look in great shape. No crimped, kinked, or damaged wires at all that I can see. The 7 pin connector was very weathered and worn, so I replaced it with a brand new connector. Plugged it in to my TV and got no lights. Double checked TV plug, and all pins are working properly. Did some quick troubleshooting. Tested connectivity between ground pin and trailer frame. No connection there. Also checked connectivity from pin to pin on trailer pigtail. I get signal between ground, RH and LH blinker pins,like all 3 are connected together. So yeah. That's a problem...

    Any pointers or common problem points to check would be helpful. Where is the main ground connection supposed to be? Figured I'd check that first. It appears that the wires run through the trailer frame, so hard to tell where they come out..
     
  2. Fless

    Fless Active Member

    @long_tall_texan,

    First thing to fix is the ground. Nothing's going to work right without it.

    If it's anything like my '02 Cheyenne, the main wiring bundle goes into the frame channel on the driver's side of the tongue (the hole is on the inside, not the outside of the frame channel). Near that should be the ground from the battery wires (or connector) on a screw to the frame; take that ground connection apart, check, clean, and reassemble.

    EDIT: You can create a temporary ground between your TV by using jumper cables between the trailer frame and a good ground on the TV. That will tell you a lot about the ground.

    When you're testing for continuity between trailer connector terminals, you should remove all light bulbs. In fact, after the ground continuity issue is resolved, I'd be testing each bulb with some alligator clips and a 12v battery to be sure all filaments work correctly.

    Good luck, and let us know what happens.
     
    Last edited: Nov 5, 2017
    long_tall_texan likes this.
  3. long_tall_texan

    long_tall_texan New Member

    5
    0
    Oct 21, 2017
    DFW Metro
    Thanks. Maybe that's my problem right there. No ground connection at the tongue at all. I don't have a battery installed yet. Previous owner removed it. Anyway, here's a pic of where the battery wires should plug in, and the wires going into the frame channel like you described. Should the white wire be grounded here?
     

    Attached Files:

  4. Fless

    Fless Active Member

    Mine's wired a little differently. The white wire from the battery connector goes directly to a ground connection on the frame, but I don't think I'd do anything with yours since it looks factory.

    However, there is that Scotchlock connector on the black wire -- can you tell where the smaller gauge wire goes?

    And the black wire that is connected to the blue wire, that should be for the electric brakes. The black wire looks awful small for a brake wire.

    For now, just wondering on those two, but I doubt that's the problem. And keep the battery out of the equation for now.
     
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  5. Fless

    Fless Active Member

    One other thing to check, if you haven't already done it, would be to follow the frame underneath all the way back, looking for wires coming out of the box frame. A bad ground there could cause all of this.
     
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  6. long_tall_texan

    long_tall_texan New Member

    5
    0
    Oct 21, 2017
    DFW Metro
    The 2 small guage wires are splices to black and blue - +12V and E-Brake. They run to the emergency brake box on at the hitch. I'll check under that channel all the way back.
     
  7. Fless

    Fless Active Member

    That sounds right, the breakaway wiring.
     
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  8. Boatnman

    Boatnman Well-Known Member

    1,220
    244
    Jan 19, 2017
    western Colorado
    Between the ground pin on the new 7-pin connector on the trailer and the trailer frame? If so, that's the problem. The 7-pin connection basically makes the trailer lights part of the TV's light system. If the TV's ground is not reaching the trailer's frame, then the trailer lights won't function.

    Having a battery or not should not affect the trailer lights. The ground wire from the trailer's 7-pin connector should be attached to the frame somewhere. As Fless suggested, put a jumper between the TV and the trailer frames which will add the trailer frame to the TV's ground system.
     
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