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  1. Custom Fit Vehicle Wiring
  2. Tekonsha
  3. Custom Fit
  4. Trailer Hitch Wiring
  5. 4 Flat
  6. No Converter
T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

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

Item # TK37FR
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Custom Fit Vehicle Wiring

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Tekonsha No Converter Custom Fit Vehicle Wiring - TK37FR
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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 ModuLite reduces strain on wiring system. 1-800-940-8924 to order Tekonsha custom fit vehicle wiring part number TK37FR 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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Tekonsha Custom Fit Vehicle Wiring - TK37FR

  • Custom Fit
  • Trailer Hitch Wiring
  • 4 Flat
  • No 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
    • Run hot lead to car battery
  • Includes ModuLite power module that 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: 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 tail lights on both the driver's side and passenger's side. You will need to remove the tail lights 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 your rear cargo area.

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 Power Module

A ModuLite power module is built into this T-One connector. 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.

118815 Tekonsha T-1 T-Connector - 4 Wire - Modu-Lite Converter Included

Installation Details TK37FR Installation instructions

This Product Fits The Following Vehicles

California residents: click here

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

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.

Video Transcript for Review of Tekonsha Custom Fit Vehicle Wiring - Trailer Hitch Wiring - TK37FR

Ellen: Hey everyone, I'm Ellen 00:00:01 here at We're going to be taking a look at the Tekonsha T-One Vehicle Wiring Harness. This allows you to transfer your lighting functions from your towing vehicle into your trailer. So that way you can have your brake lights, turn signals and your running light signals transferred from one to the other. That lets another drivers know what's going on, lets them be able to see you and also keeps you compliant with all state and federal laws.So this is a custom fit design. So we won't have to worry about any cutting or splicing into our factory wiring, saves us some headache and some issues, especially if you want to take this out of your vehicle, maybe later on down the road you decide you don't really want to use that anymore, you can always remove it without really much issue at all.So let's take a closer look at it and make sure that this is going to be a kit for you.

This is a custom fit again for the 2019 through the current Volkswagen Arteon. So it will fit in with that factory wiring, just plug it in line with your taillight wiring and the way it gets its name is from this portion, it's shaped like a T. So that's how we get the T wiring harness from. Green and white goes to the passenger side, yellow and brown goes to the driver's side.The thing that we're really going for is going to be our 4-pole here is this is what attaches to our trailer wiring, has a attached cap to keep that protected from any dust and grime that can get in there and water and other things. So will able to keep it protected.

And then this is going to be the brains of the operation. This is our module box. It's where all the circuits go through, all our signals get transferred to a usable system or a usable signal at our 4-pole.This helps to protect our vehicle from any backfeed or shorts that might arise on our trailer sides. We don't have to worry about anything with that. And it's also protected by a fuse.

So if there's any power surges or anything, it's going to blow that fuse rather than the electrical system in our vehicle, so it's going to be doubly protected in that respect. Does come with a 15 amp fuse to go in line and that's just going to connect in between our wiring and the battery on our vehicle. So it does come with that bulk wire to run up to your engine bay.And this is going to typically run outside of the vehicle. You want to keep away from anything hot or moving like your exhaust or your suspension. And you also want to find a nice spot to mount up your module box.

Comes with some double-sided tape. There's also a small screw to make your ground connection. That's pretty much all there is to it for the install. As far as the amperage with this light, it does give you five amps per circuit for the stop and turn lights, 7.5 for the tail lights. But that's pretty much going to do it for our look at the Tekonsha Vehicle Wiring Harness. Thanks for watching..


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Info for this part was:

Employee Lindsey S
Edited by:
Lindsey S
Employee Kathleen M
Installed by:
Kathleen M
Employee Wilson B
Updated by:
Wilson B
Employee Alexander C
Written by:
Alexander C

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