Recommended 4-Way Wiring Harness and Mounting Bracket for a 2015 Toyota Sienna LE

Question

Question:

Hey there, just installed a Curt 13343 on our 2015 Sienna LE and realize it doesn't have a wiring harness mount which seems like will make this option more difficult. Any suggestions?

asked by: Max B

0

Expert Reply:

Hey Max. To attach the T-One Vehicle Wiring Harness item # 118648 to your new Curt Hitch item # C13343, you'll need the No-Drill Mount Bracket item # 18136 and the Mounting Bracket 4-Pole Flat item # 18144.

The No-Drill Mount Bracket item # 18136 uses a band clamp to securely attach to the square crossbar on the Curt item # C13343. The Mounting Bracket 4-Pole Flat item # 18144 has a matching bolt hole pattern and will put your 4-way connector in a convenient location.

The T-One Vehicle Wiring Harness item # 118648 is confirmed to fit the 2015 Toyota Sienna LE. It will connect to the wiring behind your rear tail lights without cutting or splicing. This harness will give you a 4-way connector that is capable of controlling your trailer's lighting functions.

What kind of trailer are you pulling?

You can add this information, along with any other questions you have, where it says Reply to Jerred H.

expert reply by: Jerred H

0

18136
(click to enlarge)

Max B.

12/15/2025

Thanks Jerred, incredibly helpful! We'll be pulling an Rpod 178 (~2600 lbs, braked) with our 2015 Toyota Sienna some of the time, and a 13' fiberglass camper (1500 lbs, unbraked) most of the time.

Max B.

12/15/2025

On that note, we are also looking to add a 7 pin adapter, which has been addressed in the other post by one of your teammates. Thanks!

Jerred H.

12/15/2025

@MaxB You're welcome, happy to help! To add a 7-Way to your Sienna you'll need the T-One Vehicle Wiring Harness item # 118648 and the Universal Installation Kit for Trailer Brake Controller item # ETBC7. The kit includes a pre-wired 7- and 4-way trailer connector. This kit requires you to have a 4-way flat trailer connector and plugs directly into it. You will then connect the blue wire to the blue wire on the brake controller, connect the black wire to the positive post on your Sienna's battery, the white wire to a suitable ground, and the yellow wire to the accessory circuit. This kit includes all the wiring, connectors, and circuit breakers you'll need. To attach it to your hitch, you'll only need the No-Drill Mount Bracket item # 18136. Since you're towing a trailer with brakes you'll also need a brake controller. I recommend the Redarc Tow-Pro Liberty Brake Controller w/ Universal Wiring Harness item # RED52VR. This is a proportional brake controller that activates your trailer's brakes when your Sienna brakes or decelerates. The reason the Tow-Pro Liberty is the best option is because of its unique installation method where the only visible portion is the control knob that's about the size of a nickel. The main unit is hidden away inside your dash to be completely out of the way and out of sight.

Helpful Links

tv-install-trailer-wiring-2016-toyota-sienna-118648.aspx

tv-install-universal-installation-kit-for-trailer-brake-controller-2015-toyota-sienna-etbc7.aspx

Max B.

12/18/2025

@JerredH unfortunately I'd already bought the 118498 connector before I realized we might want the brake controller option, should I trade it in?

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