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: $65.26
You Save: 39%
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.

This item qualifies for Free Shipping
Shipping Weight: 1.8 lbs
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. 1-833-496-1390 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 (12)
  • Q & A (0)
  • Photos
  • Why etrailer?

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:  4.8 out of 5 stars   (12 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.


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.


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.

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.

2017 Chevrolet Volt

Very fast shipping and the price could not be beat.


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


Great product. Thanks.






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...
  • Draw-Tite Trailer Hitch Receiver for 2017 Chevrolet Volt Difficulty DIY VS Professional Installation
    The Draw-Tite Sportframe Trailer Hitch Receiver # 24947 will fit your 2017 Chevrolet Volt. It ranks a 10/10 on the difficulty due to the amount 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...
    view full answer...
  • Recommended Towing Package For A 2018 Chevrolet Volt
    When installing a towing package on your 2018 Chevrolet Volt The Draw-Tite Sportframe Trailer Hitch Receiver - Custom Fit - Class I - 1-1/4 inch # 24947 does not come with the wiring it is sold separately. The trailer hitch has a bolt-on installation that requires no welding, the hitch has a black powder coat finish that covers the e-coat base for a superior rust protection. The T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118726 has a simple plug and play installation...
    view full answer...
  • Trailer Hitch and Wiring Recommendation for 2017 Chevy Volt
    For your 2017 Chevy Volt we have the Draw Tite hitch part # 24947 as a confirmed fit that has a towing capacity of 2,000 lbs. As long as your vehicle owners 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 # 3593 and then...
    view full answer...
    Image 1 for
  • 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
  • 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?

  • Why

    At we guarantee:
  • Real product know-how.

    We make sure that the products we sell are what we say they are, and that they work the way they are supposed to work. Get real advice from a real person who has the knowledge and expertise needed to solve your problem.
  • Most detailed, accurate custom fit vehicle wiring information available.

    Because we take providing accurate product information seriously, we take our own detailed product photos, demo videos and installation videos, as well as verify measurements, instructions, and vehicle fit information.
  • Installations, made easy.

    We love helping people and have the most highly-trained customer service, hands-on experience, step by step videos and installation instructions.
  • Fast shipping.

    Your order is automatically routed to get out of our warehouse and to your door as quickly as possible. Receive free shipping on orders over $99.
  • Personalized service for life.

    We provide one-on-one, personalized service from the ordering process through the life of your product.
  • Trusted since 1946.

    We've been serving customers since our parts store first opened in 1946 and continue to be recognized by our customers, our vendors and third parties for exceptional service.
  • Returns Policy

    Need to return an item? No problem. Please read our Returns Policy for more information.

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 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

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.

Product Experts Available Now!
Call 1-833-496-1390