bing tracking image
  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 # 118726
Our Price: $68.62
You Save: 41%
Custom Fit Vehicle Wiring

Will this fit?

To see if this custom-fit item will work for you please tell us what vehicle you'll use it with.

Shipping Weight: 1.8 lbs
Add to cart
In Stock
118726 - Custom Fit Tekonsha Custom Fit Vehicle Wiring
zoom in icon
slider vertical icon
zoom out icon
Comment field cannot be left empty.
Name field cannot be left empty.

Thank you! Your comment has been submitted successfully. You should be able to view your question/comment here within a few days.

Error submitting comment. Please try again momentarily.

Product Images

In Use/Installed

Need help with installation?
Locate installers near me
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 ModuLite reduces strain on wiring system. 1-800-940-8924 to order Tekonsha custom fit vehicle wiring part number 118726 or order online at Free expert support on all Tekonsha products. Great prices and Fastest Shipping for T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector. Custom Fit Vehicle Wiring reviews from real customers.
  • All Info
  • Reviews (15)
  • Q & A (0)
  • Photos

Tekonsha Custom Fit Vehicle Wiring - 118726

  • 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 ModuLite 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
    • Connect hot lead to battery
  • Includes ModuLite power converter to ensure that your vehicle's wiring matches that of your trailer
    • Powered module connects 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: 5 amps per circuit
    • Tail lights: 7.5 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 tail light assemblies 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 flat connector will be stowed beneath your vehicle, near the trailer hitch. A mounting bracket (sold separately) is recommended to keep the connector secure.

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.

118726 Tekonsha T-1 T-Connector - 4 Wire - Modu-Lite Converter Included

Installation Details 118726 Installation instructions

This Product Fits The Following Vehicles

California residents: click here

Customer Satisfaction Score:

Customer Reviews

T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - 118726

Average Customer Rating:  4.9 out of 5 stars   (15 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 ModuLite reduces strain on wiring system.


The kit worked as designed. The connector cable length is a bit excessive so there is a risk of dragging on the road if not properly secured.

2017 Chevrolet Volt

Perfect product and great video instructions for the trailer hitch and trailer light wiring in the car. Got the hitch a couple of hours ago and it is installed. Lighting works great. Thank-you.


Unfortunately the first shipment of the lighting kit was defective, with one of the trailer lights not working. etrailer quickly shipped out a replacement that worked perfectly. Installation was straightforward and the video instructions provided by etrailer were invaluable.

2018 Chevrolet Volt

This product has worked perfectly for my 2018 Chevy Volt. I previously tried using the CURT 56315, two of which stopped working soon after installation. This harness has been on my vehicle for over a year now with no problems.


After one year of usage, the contacts get some oxidation, scrub and file them a bit and all works. Installation was easy and well-described.

Chevrolet Volt

Best wiring kit I have ever installed. The T-connectors are so much better than the old splicing garbage. Note for the Volt the instructions said to route the power to the front of the vehicle to the battery, but the battery is located in the trunk area.


Item worked well and was easy to install following the excellent video. A year on after dozens of uses and nothing to report!

2017 Chevrolet Volt

Wiring harness was a bit of work to get installed but works as advertised the only gripe I have is the video shows the guy installing the drivers side lights using a heave guage wire to snake it through the plastics down to the battery. I did not have wire on hand so went ahead and took apart the plastic paneling on drivers side aswell as passenger


Easy to install, and worked like a char m.


Great product. Thanks.



2017 Chevrolet Volt

Very fast shipping and the price could not be beat.




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

  • Troubleshooting Trailer Wiring Harness Installation Where Opposite Turn Signals Engage on Trailer
    The brown wires on your wiring harness correspond to the tail lights on the vehicle, so that's not going to be what is causing the issue. I'm not sure which wiring harness that you're using, but the odds are that the wires connected to the turn signals are reversed, which would cause the trailer to be getting the wrong signals. If this is a trailer wiring harness like the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118726 you'll just want to unplug them and swap...
    view full answer...
  • Curt Trailer Hitch Receiver for 2017 Chevrolet Volt Difficulty DIY VS Professional Installation
    The Curt Trailer Hitch Receiver # C11436 will fit your 2017 Chevrolet Volt. It ranks a 10/10 on the difficulty due to the number of parts that need to be removed to install the hitch and the trimming required of the panels that the hitch will pass through. I have attached the video of the installation we completed on a Volt for you to determine if it something that you would feel comfortable doing yourself. We do not have installers that we recommend but I suggest going to the Curt website...
    view full answer...
  • Trailer Hitch Recommendation for 2019 Chevy Volt
    For your 2019 Chevy Volt I recommend the 2 inch EcoHitch part # 306-X7338 as it gives you the more popular 2 inch hitch size but also because it installs behind the rear license plate which gives you a concealed hitch that doesn't affect ground clearance either. If you were in need of trailer wiring as well we have the # 118726 which is custom fit for a very easy install and also has a very reliable converter box too so it will last you a long time.
    view full answer...
  • Recommended 2" Receiver Hitch for a 2018 Chevy Volt
    Yes, there is a hitch for your 2018 Chevy Volt that will allow you to mount a wheel chair carrier to it. It is the EcoHitch Invisi Trailer Hitch Receiver item # 306-X7338. This hitch is custom fit and bolts to your Chevy with included hardware. I really like the Ecohitch because it mounts behind your rear bumper cover and the receiver is hidden by your license plate when not in use. You will never know the hitch is there when you are not using an accessory or towing. This hitch has a...
    view full answer...
    Image 1 for Image 2 for
  • Trailer Hitch and Wiring Recommendation for 2017 Chevy Volt
    For your 2017 Chevy Volt we have the Curt hitch part # C11436 as a confirmed fit that has a towing capacity of 2,000 lbs. As long as your vehicle owner's manual states your vehicle is also rated for the weight of your trailer and motorcycle this would be a great solution. For trailer wiring you'd then want the Tekonsha kit part # 118726 because it does not require any splicing and it also comes with our most reliable converter box. For a ball mount you'd want the part # C45521 and then...
    view full answer...
    Image 1 for
  • Recommended Trailer Hitch Receiver and 4-Way Wiring For a 2018 Chevrolet Volt
    I recommend installing the EcoHitch Invisi Trailer Hitch Receiver # 306-X7338 on your 2018 Chevrolet Volt. This 2" receiver hides behind your license plate and includes a fold up license plate bracket for easy access. Because it sits behind the license plate it does not hang down like the 1-1/4" Curt # C11436 which can drag on tall curbs or transitions you encounter. We have a link "Locate installers near me" below the photos and videos on our product pages which will allow you to search...
    view full answer...
  • Can a Trailer Hitch Receiver Be Welded Onto Impact Structure Behind Rear Bumper For 2017 Chevy Volt?
    The impact structure behind the rear bumper fascia of your 2017 Chevrolet Volt is not structurally strong enough to support a receiver. This is why instead of replacing the impact structure the available Curt # C11436, Draw-Tite # 24947 and EcoHitch # 306-X7338 mount behind the structure. The impact structure is also designed to help absorb impact in a collision while the receiver is designed to support the weight when towing or carrying additional weight. I do feel the EcoHitch is the...
    view full answer...
  • How to Carry 4 Bikes with a 2017 Chevrolet Volt
    It sounds like you're trying to carry four bikes on a 2017 Chevrolet Volt. I have a solution for you, but the Volt is limited to only 2 bikes on a hitch mount carrier and we do not have any fits for roof racks to carry bikes. The only option we have to carry all 4 bikes is to install a hitch receiver on the Volt and tow the Yakima Rack and Roll # Y08106 behind it carrying the bikes. The Rack and Roll is basically Yakima roof rack on wheels so it can be used to carry a variety of things...
    view full answer...

Do you have a question about this Custom Fit Vehicle Wiring?

Info for this part was:

Employee Lindsey S
Edited by:
Lindsey S
Employee Jeff D
Installed by:
Jeff D
Employee Joshua S
Video Edited:
Joshua S
Employee Jacob T
Video Edited:
Jacob T
Employee Wilson B
Updated by:
Wilson B
Employee Isabelle B
Updated by:
Isabelle B
Employee Alexander C
Written by:
Alexander C
Employee Brent H
Test Fit:
Brent H
Employee John A
Test Fit:
John A

At we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.