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Taffy_C's avatar
Taffy_C
Explorer
Feb 20, 2021

Problems with 7 Pin Connector

Hi There,

Having issues with the 7 Pin trailer connection between my trailer and TV. I can't seem to get all contacts connecting at once - I I jiggle the connection slightly I can get brakes connected but I lose one or more light connections and vice-versa.

I've tried using a very find grade wet/dry sandpaper to clean the contacts but that only brought minor improvements. I'm thinking that maybe the connections are too sloppy and maybe I need to replace the trailer connector plug. The trailer is 18 years old.

I'd welcome any suggestions on this - not sure how difficult it is to replace the connector too. Also, because I have a hensley hitch that added a few inches to the trailer length, I don't have any room to lose length on the electrical cable (which I figure might happen when I replace the connector plug). If anything I need to make it longer.

Any help much appreciated,

Daniel.

19 Replies

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  • JRscooby's avatar
    JRscooby
    Explorer II
    Feb 21, 2021
    Diamond c wrote:
    If the prongs have a split in the middle of them take a small flat blade screw driver, put it in the split and spread them so that they fit tighter. This works for me on the pigtail of my tractor trailer.


    Commercial with round holes/pins is much easier.
    I have used 2 pair of needle-nose pliers to bend a slight V in the length of the blade, then flatten the ends so the plug will start back on. Less work to replace the plug, and likely only last for 1 trip.
  • Gdetrailer's avatar
    Gdetrailer
    Explorer III
    Feb 21, 2021
    You can try to clean them, scrub them, adjust the prongs but after a while weather and age takes a toll on the plugs..

    For $6 and a little bit of your time you can just replace the plug and be done with the issue for quit some time..



    FOUND HERE

    For less than $30 you can buy not only the plug but the entire harness with the plug molded in to the harness with 8ft of wire..



    FOUND HERE

    That one looked interesting since it has double prong contacts in the plug rather than standard single prong contacts..
  • Diamond_c's avatar
    Diamond_c
    Nomad
    Feb 21, 2021
    If the prongs have a split in the middle of them take a small flat blade screw driver, put it in the split and spread them so that they fit tighter. This works for me on the pigtail of my tractor trailer.
  • rr2254545's avatar
    rr2254545
    Explorer
    Feb 21, 2021
    Had the same problem replaced the female plug on the RV, no problems since then - it was not the cord -
  • Taffy_C's avatar
    Taffy_C
    Explorer
    Feb 21, 2021
    Thanks for the replies. Pretty sure the wiring is fine so I guess I'll start with the screwdriver and WD40. Hopefully its that simple:)
  • MitchF150's avatar
    MitchF150
    Explorer III
    Feb 20, 2021
    That happened to me a long time ago.. I took a small flat blade screw diver and pulled the 'female' side prongs out in each socket and then sprayed some wd40 into the plug and that fixed it.. It was only a plug connection issue in my case, but if it's a wiring issue, then more work will need to be done to diag it..

    Good luck, Mitch
  • deltabravo's avatar
    deltabravo
    Nomad
    Feb 20, 2021
    Some plugs on trailer cords have an undersized diameter on the plug, so they fit really loose and sloppy in a truck OEM plug.

    I had the same problem. I replaced the entire cord / molded plug with a different brand, problem solved.
  • jdc1's avatar
    jdc1
    Explorer II
    Feb 20, 2021
    Sometimes I have to use a screwdriver to bend the prongs for better contact. I use lithium grease on my wife's plug-in Prius cord, and that really helps.

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