Suggestions for trailer brake wiring

Discussion in 'Towing' started by Dave Aley, Dec 18, 2017.

  1. Dave Aley

    Dave Aley Newbie

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    Feb 7, 2017
    Albuquerque, NM
    I have a '97 dually. It has a brake controller that was there when I bought it, but it doesn't work. There's a 6-pin in the bed that was used with a gooseneck, and I've replaced the 6-pin on the rear bumper with a 7-blade to match my trailer. The wiring in the back is not very well done (I was surprised when I wired up the new connector and all the lights actually worked), so I'm going to rewire the trailer brakes and redo the rat's nest of wiring for the lights.

    I'm planning to put a Tekonsha P3 from my (soon to be sold) '03 Suburban into the dually, and I'm looking for the best way to run new wires from the cab, to the engine compartment, and back to the connectors. Any suggestions - wire types, routing, best places to tie in to the existing harness?

    Also, since I've never towed a gooseneck trailer, I'm wondering if the 6-pin round connector in the bed is standard for those. I'll keep the connector in the bed if it's likely to fit a gooseneck - I don't know when I'll ever tow one, but no sense deleting the connector as long as the truck has the hitch. If I'm better off with a 7-blade connector in the bed, though, now would be a good time to switch while I'm already crawling under the truck with wiring tools.
  2. SierraDully

    SierraDully Newbie

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    Dec 9, 2017
    Edmonton, Alberta, Canada
    What I've always used is just a home made pigtail adapter that will plug into one trailer connector and have an output of the other type of connector.

    So if there's a round style male connector attached to the truck then I would make an adaptor that has a round female style plug on one end, 6" of wiring, then a flat style male connector on the other end. Solder all connections, Wrap the wiring with loom or heat shrink and it looks nice and neat.

    The one I have now has been kickin around for about 10 years and still works great. Don't use it all that often.

    I made one because I have a ton of that kinda stuff around the shop, but they can also be bought. It's the same idea as the adaptor that plugs into a regular trailer wiring connector and has an output for the small 4-wire connector.

    In my experience there is no "standard" connector for goosenecks. Different manufacturers/customers will order different plugs for their preferred set up. Can come in handy to have both, especially if you frequently tow different trailers.
  3. Tavi

    Tavi Vehicle enthusiasts

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    Apr 11, 2013
    North east NM
    Agreed, there is no standard. A better definition would be most common. I would say the most common I have seen in recent years is the four pole flat and the 7 blade round. However as @SierraDully mentioned. Adapters are your best friend.

    But just match the trailers you tow most.
  4. Supercharged111

    Supercharged111 I'm Awesome

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    Aug 20, 2015
    97 will already have the necessary wires there for a 7 pin unless you want bigger wires.
  5. lxe4

    lxe4 Newbie

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    Oct 15, 2015
    all or most or many of these trucks came with all the wiring in place. who know whats been done to yours, you mention some stuff previously installed. they came with a nice orange i want to say 10 guage wire and a blue maybe 12 guage that run from the firewall at the fuse panel under the hood to the back. they originally had them tucked away and hidden in the factory light harness.

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