4-pin to 7-pin Adapter Wiring

Discussion in 'Etrailer.com Trailers and Towing Forum' started by ben schmaus, Mar 3, 2018.

  1. ben schmaus

    ben schmaus New Member

    Feb 18, 2018

    I have a 2018 AWD Toyota Highlander with a 4-pin connector.

    I'm going to be towing a popup with a 7-pin connector so I'll need an adapter. What I'm wondering is if it's reasonable to simply use the adapter without connecting the wires for brakes, aux power, and reverse lights.

    The trailer is 15.5 feet with a dry weight of ~1875lbs and GVWR of 2750lbs. I was considering getting a sway bar and a 4 to 7 pin adapter and simply not connecting the additional wires (saving myself some work and purchasing a brake controller). Does this sound like a reasonable approach?

  2. NMroamer

    NMroamer Active Member

    Apr 21, 2016
    Albuquerque NM
    I would wire for the brakes. Not just for safety but for peace of mind. Don't want to depend on TV to stop everything.
  3. jnc

    jnc Welcome from New Hampshire

    You will want to have Trailer Brakes! 2000 Lbs will push your Toyota around enough never mind a fully loaded camper.
  4. gardenbliss

    gardenbliss Well-Known Member

    Dec 9, 2013
    San Diego
    I tow with a highlander and was advised to definitely switch to 7 pin to protect car brakes.
  5. xxxapache

    xxxapache Well-Known Member

    Jul 30, 2008
    I would get brakes if I could....With that said, I have towed 2500lb or so trailers without brakes with my compact Toyota pickup for over 20 years with no worries or issues.
  6. tenttrailer

    tenttrailer Art & Joyce - Columbus, O

    Jul 18, 2013
    Thornville, OH
    You can buy a 7 pin connector that already has a pigtail 4 wire connector that will connect to you 4 wire connector. Giving you RT, LT, Brake and running lights.

    I would then run the brake wire to a controller and run a battery wire. If your camper has backup lights I would run them. You need brakes the highlander does not have enough brakes. I think if you look in your owner's manual you will find the highlander is limited to tow a 2K trailer, maybe 2.5K without brakes. Be safe have a enjoyable memory.
  7. ben schmaus

    ben schmaus New Member

    Feb 18, 2018
    @gardenbliss what brake controller did you install?

    And did you do the install yourself? If so, curious if you have any tips for routing the wires under the Highlander.
  8. Raycfe

    Raycfe Waterford Ct.

    Oct 3, 2007
    Waterford, Ct
    As others have stated ....... if your trailer has brakes ....use them. That said, start with instead of an adapter, a seven pin socket that the flat four will just plug into and have the 3 extra wires. You will able to use the trailer and save up for the brake controller and wiring to finish up at a later date.
  9. Snow

    Snow Well-Known Member

    Jul 19, 2007
    Fyi.. In just about every State and Province the law states that if the trailer has brakes, they must be operational, regardless of whether the trailers GVWR is below the weight at which brakes are required. ..
  10. Fbird

    Fbird Active Member

    Sep 10, 2017
    Ferndale MI
    yes every state is different, its your responsabilty to know and comply to their laws, so if you live in Michigan and goto ohio you have to comply with ohio's laws. I know legally this doesn't apply to you. but understand the commercial laws are any trailer 3000 lb axle or greater requires brakes, when the gvwr of the trailer is 40% or more than the gvwr of the tv brakes are required. trailer brakes are bennificail cause they save wear and tear on the tv and are safer, even though I don't feel or notice my pup behind me in my 3/4 pu it does add to my braking distance. in a emergency braking situation it can make a difference and it will help keep the pup behind you in that incident. if a trailer starts to sway the brake controller can be used to bring it back under control.
  11. Snow

    Snow Well-Known Member

    Jul 19, 2007
    You only have to comply with your home State in this case...
    Fless likes this.
  12. ben schmaus

    ben schmaus New Member

    Feb 18, 2018
    Thanks for the thoughts. Lots of good reasons to have the brake controller and use the electric brakes; I'll wire a controller into my TV.
    jnc likes this.
  13. jnc

    jnc Welcome from New Hampshire

    I'm happy you have decided to get the controller. You will be able to see the value of having the controller setup when you are dialing it in to your trailers needs.
  14. Sharpie

    Sharpie Member

    Nov 2, 2009
    Ontario Canada
    Etrailer.com has a sale on brake controlers. this is the model I bought it works great and Is easy to use.
    Tekonsha Prodigy P3 Trailer Brake Controller - 1 to 4 Axles - Proportional It's $136.00 plus tax with free shipping.

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