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  1. Custom Fit Vehicle Wiring
  2. Tekonsha
  3. Custom Fit
  4. Trailer Hitch Wiring
  5. 4 Flat
  6. Powered Converter
T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

Item # 118629
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Custom Fit Vehicle Wiring

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T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector Custom Fit 118629
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Quickly and easily install a 4-way trailer connector on your vehicle with this custom wiring harness. T-One connector plugs directly into existing wiring. Powered converter reduces strain on wiring system. 1-800-940-8924 to order Tekonsha custom fit vehicle wiring part number 118629 or order online at Free expert support on all Tekonsha products. Guaranteed Lowest Price and Fastest Shipping for T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector. Custom Fit Vehicle Wiring reviews from real customers.
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  • Reviews (9)
  • Q & A (0)
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  • Why etrailer?

Tekonsha Custom Fit Vehicle Wiring - 118629

  • Custom Fit
  • Trailer Hitch Wiring
  • 4 Flat
  • Powered Converter
  • Tekonsha

Quickly and easily install a 4-way trailer connector on your vehicle with this custom wiring harness. T-One connector plugs directly into existing wiring. Powered converter reduces strain on wiring system.


  • Provides a 4-way flat trailer connector at the back of your vehicle to power your trailer's signal lights
    • Compatible with 5-pole, 6-pole and 7-pole adapters (sold separately)
  • Connects quickly and easily
    • Locate connection points behind tail lights
    • Plug in T-connector
    • Run hot lead to car battery
  • Includes ModuLite to ensure that your vehicle's wiring matches that of your trailer
    • Powered module connects directly to battery to avoid overloading vehicle's electrical system
  • Constructed of 16-gauge bonded wire
  • Comes with dust cap for 4-way flat connector


  • Maximum amperage:
    • Stop/turn lights: 2.1 amps per circuit
    • Tail lights: 5.6 amps per circuit
  • 1-Year limited warranty


This custom-fit T-One connector plugs into your vehicle's wiring harness, which is located behind the driver's-side and passenger's-side tail lights. You will have to remove the threshold panel and pull back the felt trunk liner to access this harness.

T-One Connection Location Points Behind Tail Lights

Once you've plugged in the T-connector, run the hot lead up to your car battery. Connect the lead to the included fuse holder, and then connect the fuse holder to the positive terminal on your battery and insert the provided fuse.

Once installation is complete, the 4-way connector will be stowed in an out-of-the-way location within your trunk.

It is recommended that you use a small amount of grease on all electrical connections - the plugs on your automobile and the 4-pole connector itself - to help prevent corrosion.

ModuLite Powered Tail Light Converter

A ModuLite power module is built into this T-One connector. Because most trailers run on a two-wire system - wherein the brake and turn signals are carried on one wire - the separate brake and turn signals from your vehicle's three-wire system need to be combined so they are compatible with the wiring system of your trailer. This power module functions as a tail light converter to combine the brake and turn signal functions of your automobile so that they run on one wire to properly activate your trailer's tail lights. Note: This will not affect how the tail lights on your vehicle operate.

With a ModuLite, your trailer's lights will be powered without overloading your vehicle's electrical system. Because the module draws power directly from your car's battery and bypasses the electrical routes that are used by a basic wiring harness, there is virtually no draw on your tail light circuits.

118629 Tow Ready T-1 T-Connector - 4 Wire - Modu-Lite

Installation Details 118629 Installation instructions

This Product Fits The Following Vehicles

California residents: click here

Customer Reviews

T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - 118629

Average Customer Rating:  4.8 out of 5 stars   (9 Customer Reviews)

Quickly and easily install a 4-way trailer connector on your vehicle with this custom wiring harness. T-One connector plugs directly into existing wiring. Powered converter reduces strain on wiring system.


Our order was shipped as ordered. Easy company to work with.

2018 Subaru Impreza

Fast delivery, well packaged.
The website
offered a number of Wiring Kits that were supposed to fit my vehicle. However the one I picked did not fit my wire harness ( I hope they removed that one from the list). Every one was very nice and they suggested another harness, that did fit the vehicle correctly. They also provided instructions for the return of the incorrect harness. Bottom line is that it held me up an extra week, I had to pay shipping on the 2nd harness and will probably have to pay the return shipping all because the website
was wrong.

This wiring harness is a fit for the sedan, but not the wagon model as mentioned in our fit guide.
-- Etrailer Expert Mike L - 07/08/2019

Subaru Impreza

Installed in 2020 Subaru Impreza. Works just as advertised. The hardest part is ripping out the plastic under the doors and feeding the hot wire. Expect an install of 45 min to an hour. If Subaru had a hot wire lead pre-installed in the trunk, it could be installed in under 5 min.

2018 Subaru Impreza

Thank you, we received it in a timely m anner!


Great service


Lengthy install time, but it works just as it should


easy install

2019 Subaru Impreza



See what our Experts say about this Tekonsha Custom Fit Vehicle Wiring

  • Does Rear Panel of 2017 Subaru BRZ Come off To Install Draw Tite Hitch
    Yes, to install the Draw Tite hitch part # 24935 that you referenced the rear panel does have to come off. In the instructions link that I attached this entire process is covered. For trailer wiring you then would want the part # 118629 which is a confirmed fit for your 2017 Subaru BRZ and would work well.
    view full answer...
    Image 1 for
  • Can 4-Way Mounting Bracket # 18140 be Used with 4-Way Harness # 118269
    Yes, you can use the 4-way mounting bracket part # 18140 with the 4-way part # 118629 that you referenced but you'll also need the additional bracket part # 18144 and you'll be set.
    view full answer...
  • Trailer Hitch Recommendation for 2018 Subaru Impreza to Tow Motorcycle Trailer
    We have hitches available for your 2018 Subaru Impreza that would be able to handle the weight of a 500-600 lb motorcycle carrier like the Draw Tite part # 76209 as it has a 675 lb tongue weight capacity, but from the research I did on your vehicle it looks like it's limited to only 350 lbs of tongue weight so this wouldn't be ideal with a motorcycle carrier. Your best option would be a small trailer for carrying the motorcycle. For that you'd need wiring part # 118629 for if you have...
    view full answer...
  • Curt Trailer Wiring Harness Causes ABS Problems when Installed on a 2013 Scion FR-S
    When you are having the problems on your 2013 Scion FR-S do you have anything plugged into the Curt wiring harness # C56212? If nothing is plugged into the 4-Way then it should not be drawing any power from the vehicle tail light connections. The only thing I can think of is if there is a short it could be overdrawing the tail light connections causing the problems you are having. That would indicate a problem inside the converter. To test the harness use a circuit tester such as # 40376...
    view full answer...
  • Trailer Hitch Recommendation for 2018 Subaru Impreza
    If you have the 5-door wagon 2018 Subaru Impreza you would want the part # 76209. If you have the Sedan instead you would want the part # 24960. For trailer wiring you would want the part # 118629 for the Sedan or part # 118744 for the wagon.
    view full answer...
  • Will Curt Trailer Hitch # C113753 Fit 2015 Subaru BRZ
    I do have an option for you, however the Curt Trailer HItch Receiver # C11375 that you referenced is designed for the 2014-2016 Scion tC and will not fit your 2015 Subaru BRZ. For your Subaru I instead recommend the Curt Class I Round Tube Receiver Hitch # C11379. This custom hitch will use existing holes in the vehicle's frame for a no-drill installation. All the needed hardware is included. I have attached the written installation instructions that you can also check out. If you will...
    view full answer...
  • What is the Most Hidden Hitch on a 2020 Subaru Impreza
    By far the most hidden hitch we have for your 2020 Subaru Impreza is the EcoHitch Hidden Trailer Hitch Receiver part # 306-X7350 this is a custom designed hitch with a 2" receiver tube. This hitch remains completely hidden with the exception of the receiver tube opening (see photo). It is made of recycled materials to lighten the carbon footprint and will work with all types of hitch mounted accessories like bike racks and cargo carriers. If you're going to be hauling a small trailer or...
    view full answer...
  • Class II Ball Mount with Highest Rise Available for a 2018 Subaru Impreza
    The Class II ball mount we carry that's closest to the 7 inch rise you need is part # C45014. However, it only offers 5 inches of rise. I've also attached our article on determining the amount of rise you need. You want to measure from the ground to the top of inside of your hitch receiver on your Subaru. Then compare that measurement with the distance from the ground to the underside of your trailer's coupler. The difference is the amount of rise you need. Just make sure both are...
    view full answer...
  • Easiest Trailer Hitch Receiver and Wiring Harness To Install On a 2017 Subaru BRZ
    The Curt Trailer Hitch Receiver # C11379 is going to be our easiest receiver for a novice installer on your 2017 Subaru BRZ. I have linked the installation instructions below that you can reference to determine if you feel comfortable installing the receiver. The EcoHitch Stealth Trailer Hitch Receiver # 306-X7293 is far more complicated to install and requires the removal of the rear fascia and impact structure to complete. I feel this is better left to those with more experience to...
    view full answer...
  • Will the Draw-Tite # 24935 be Good for Towing a Small Trailer with a 2015 Scion FR-S
    The Draw-Tite # 24935 is a confirmed fit for your 2015 Scion FR-S and has a tongue weight rating of 200 lbs and a gross towing weight of 2,000 lbs so the hitch itself would be able to handle a small trailer like the Malone MicroSport # MPG461G2. To complete a towing setup for your Scion FR-S you would need wiring like the Tekonsha T-One # 118629, a ball mount like the Draw-Tite # 3593, and a hitch ball like the 1-7/8" # 19256 or 2" # 19258. You will want to reference the linked ball mount...
    view full answer...
  • What is the Highest Rated Hitch for a 2018 Subaru Impreza for Towing and Accessories?
    The Draw-Tite Max-Frame Trailer Hitch Receiver # 76209 is a two inch trailer hitch receiver rated for 675 lb tongue weight and up to 4500 lbs towing capacity. There is no drilling required for this hitch installation. This receiver will work especially well with accessories like a bike rack or cargo carriers. The hitch pin hole is 3 inches recessed from the outermost part of the bumper which will be compatible with almost all 2 inch accessories. For your trailer hitch if you want trailer...
    view full answer...
    Image 1 for
  • Hitch, Ball Mount and Wiring for 2017 Toyota 86 for Towing and Cargo Carrier
    Draw-Tite Class I hitch # 24935 is a confirmed fit for your 2017 Toyota 86 and with it you can use ball mount # 3593. Add either 1-7/8-inch hitch ball # 19256 or 2-inch ball # 19258 depending on the coupler size on the trailer. Curt wiring kit # C56212 is a fit but instead I recommend the Tekonsha harness # 118629 because we have found their wiring products to be more reliable. An article to help you with the install is linked. For a cargo carrier I recommend the Curt # C18110 instead...
    view full answer...

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Info for this part was:

Employee Jeff D
Installed by:
Jeff D
Employee Laura H
Written by:
Laura H
Employee Wilson B
Updated by:
Wilson B
Employee Alexander C
Updated by:
Alexander C
Employee Isabelle B
Updated by:
Isabelle B

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