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

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

Item # 118517
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Custom Fit Vehicle Wiring

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118517 - Powered Converter Tekonsha Custom Fit Vehicle Wiring
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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. Call 800-298-8924 to order Tekonsha custom fit vehicle wiring part number 118517 or order online at etrailer.com. 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.
  • All Info
  • Reviews (12)
  • Q & A (11)
  • Photos
  • Why etrailer?

Tekonsha Custom Fit Vehicle Wiring - 118517

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

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 in trunk
    • 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 inside your trunk, behind the tail lights on both the driver's side and passenger's side. You will need to remove some interior trim or carpeting to access the harness. 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 within the spare tire compartment of 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.

118517 Tow Ready T-1 T-Connector - 4 Wire - Modu-Lite

Installation Details 118517 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 - 118517

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.

- 118517

Easy to install. The [online] video should be in the product's page. It really helped to install it. 817649

- 118517
2009 Toyota Yaris

This product was extremely easy to install. The YouTube video explains everything step by step. 437949

- 118517

Angela was extremely helpful on the phone and processed my order promptly. I received the hitch in 3 days! Outstanding customer service! Thank you! 400512

- 118517
2009 Toyota Yaris

We ordered a trailer hitch for our 2009 Toyota Yaris. It was easy to install and came with the light kit. Everything we needed was included. Perfect for us!! Thank you so much! Now we can tow our fishing boat, and our small utility trailer! 399383

- 118517

Donna did a great job of resetting my order to a higher shipping priority. Got it today and have plenty of time to install before we leave. 334846

- 118517
2008 Toyota Yaris

some what easy to install, the hard part is getting a power wire to the battery. In the case of a 2008 yaris sedan, there is a plug on the firewall on the passenger side upper, pull the plug drill the plug with 3/16 drill and the wire will be tight and sealed. Remove glove box, use a pick to force hole through insulation from engine side and locate from inside. Start power wire in truck follow factory wires over LR wheel house across rear floor to pass side under carpet. forward on right side rocker/floor to firewall across firewall to battery. 199067

works fine
Steve - 05/30/2016


- 118517
2010 Toyota Yaris

Very good directions simple to do . take time and don't get in hurry . 189805

- 118517
2007 Toyota Yaris

This harness in meant for the Yaris sedan, which was not obvious when the site recommended it. However, it is still using standard color coding on the wires. With a little splicing, I was able to make it work fine. The power cable was a bit of a worry as it has to be run from the battery - be prepared to spend time routing that cable and possibly drill though some metal. 171472

- 118517
2008 Toyota Yaris

Installation was pretty easy and the instructions were well laid out. One note - the wiring system requires a connection to the battery (it does not run off of the existing wiring power) and threading the power to the battery was the only pain. 58301

Everything is great. I havent had any problems or concerns. The hitch and lights have always worked perfectly.
Tony - 05/16/2014


- 118517
2009 Toyota Yaris

easy to use websight, easy to understand, very consice and to the point. excelent tips and help installing my hitch, witch I did my self in 1/2 hour. super fast delivery too.Man you guys and gals at ehitch really got it going! just awesome!!! I will recomend and use etrailer from now on, thanks again!!! 35672

- 118517
2008 Toyota Yaris

This hitch is well made and has a nice finish. It fit perfectly to the car. The two top bolts are a challenge to get started. Only due to a tight fit for your hand. E Trailer sent my order earlier than expected. They are a great company and their products are first class. 32389

- 118517

The harness connects very easily inline with the taillights. Getting the power from the battery to the trunk is a challenge if you don't want to run it on the exterior of the car or through the interior. 24575


Ask the Experts about this Tekonsha Custom Fit Vehicle Wiring

  • Why is Tow Ready T-One Harness Only Fit for a 2009 Yaris Sedan and Not Hatchback
    The Tow Ready # 119178KIT is the correct harness for your 2009 Toyota Yaris and will require minimal splicing during the installation. The Tow Ready # 118517 will not work on a hatchback because the actual connectors Toyota used are different between body models. According to my technical contact at Tow Ready, the hatchback version of the Yaris that you have uses a different connector than the sedan version. Tow Ready chose to make the hatchback version harness where it needs to be spliced...
    view full answer...
  • Installing Tow Ready T-One Trailer Wiring Harness Part # 118517 on 2009 Toyota Yaris
    The Tow Ready T-One Trailer Wiring Harness, # 118517, once properly installed will power the turn signals, brake lamps, and running lights of your trailer. Once the T-One is installed, no additional wiring will be necessary to make your trailer lights functional. I have provided a link to the installation instructions for you to review.
    view full answer...
  • Will The Tow Ready T-Connector Vehicle Wiring Harness # 118517 Fit A 2009 Toyota Yaris Hatchback
    The Tow Ready T-Connector Vehicle Wiring Harness, part # 118517, will only fit the 2009 Toyota Yaris Sedan. You will need the Draw-Tite Upgraded Circuit Protected Taillight Converter Hardwire Kit, part # 119178KIT, for the Hatchback model. This wiring harness has a taillight converter that will convert your vehicles 3-wire system to the trailers 2-wire system. It will not work on a Toyota Yaris with LED taillights. The Draw-Tite wiring harness will need to be hardwired to the vehicles...
    view full answer...
  • Does Tow Ready Trailer Wiring Harness # 118517 Require a Battery Connection on a 2009 Toyota Yaris
    The installation instructions for the Tow Ready Wiring harness, # 118517, are correct. The power wire does need to be routed and connected to the vehicle battery. The purpose of this connection is that it provides power for the trailer lights and virtually eliminates power draw on the sensitive vehicle tail light wiring. This in turn protects the vehicle wiring and other electrical components from damage.
    view full answer...
  • Can a 2007 Toyota Yaris Tow a Watercraft Trailer Using Draw-Tite Trailer Hitch # 24819
    The Draw-Tite Sportframe Trailer Hitch Receiver, part # 24819, will fit the 2007 Yaris Sedan and 3-Door Hatchback, but not the 5-door hatchback. I have included a link to an installation video for this hitch and also one to our main page for hitches for the 2007 Yaris. At the top of the page there is a drop-down menu (Select Vehicle Style) that will enable you to narrow the hitch results to just those suitable for your particular Yaris. All of the hitches we offer for the Yaris are Class...
    view full answer...
  • Comparing Draw-Tite Trailer Hitch # 24819 and Hidden Hitch # 60209 For a 2010 Toyota Yaris
    Actually, there are 4 trailer hitches available for the 2010 Toyota Yaris Sedan. I have included a link to them for you to view. And you are correct, both the Draw-Tite # 24819 and the Hidden Hitch # 60209 (no longer available) will fit. The difference between these two is that the Hidden Hitch, # 60209, comes with the correct ball mount, pin, and clip. With the Draw-Tite Hitch, you would have to purchase them separately. You actually save a little money when going with the Hidden Hitch....
    view full answer...
  • Will Curt Hitch and Drawbar fit a 2007 Toyota Saris?
    The Curt Trailer Hitch Receiver # C11060 will fit your 2007 Toyota Yaris if it is a sedan and not a 3-door hatchback. The correct ball mount for this hitch is the Curt # C45521, for which you'd also need a pin and clip, # F-4. Keep in mind that using this hitch would require the use of Curt's support straps # 18050 for non-trailer loads or you would void the warranty. Should you have a hatchback, I highly recommend using the Draw-Tite # 24819. It will not require the use of...
    view full answer...
  • Can Tow Bar Wiring on 2007 Toyota Yaris be Used to Tow a Trailer
    No the tow bar wiring harnesses do not work in reverse. In other words if you were to plug in a trailer nothing would happen. You would need to install a regular trailer wiring harness in your 2007 Toyota Yaris. If your Yaris is a sedan you can use wiring harness # 118517. If it is a hatchback then you would need a hardwire harness instead; # 119178KIT. Please note that even though there are trailer hitches available for your Yaris such as # 24819 this vehicle is not designed for...
    view full answer...
  • Will Draw-Tite Trailer Hitch # 24819 Fit a 2007 Toyota Yaris S Sedan
    If your 2007 Toyota Yaris S does not have the Aero package then the Draw-Tite trailer hitch # 24819 should fit fine. If it does have the Aero package you will most likely need to trim the area on the added fascia where the hitch receiver will be. If you plan on doing some towing, be sure to consult your owners manual to determine if you can tow with the Yaris. If you can, the correct ball mount is # 3593 and you can use pin and clip # PC2. For a 1-7/8 inch diameter ball, use # 19256...
    view full answer...
  • Trailer Hitch Recommendation for a 2008 Yaris Sedan Base Model
    Yes, I checked with Draw-Tite and the part # 24819 that you referenced is the correct hitch for your 2008 Toyota Yaris sedan base model. I attached an install video for this hitch for you to check out as well. For trailer wiring you might be interested in the part # 118517. For a 1-7/8 inch ball # 19256, or for a 2 inch ball part # 19258.
    view full answer...
  • Is There Drilling Required to Install a Hidden Hitch Trailer Hitch on a 2008 Toyota Yaris
    I checked the installation instructions for the Draw-Tite Trailer Hitch Receiver # 24819 and you will not need to do any drilling to install this onto your 2008 Toyota Yaris. I attached the installation instructions for you to check out also. You may be interested in purchasing the following products to complete your towing setup if you plan on doing some towing: Tow Ready Custom Fit Vehicle Wiring # 118517 (installation instructions attached) Hitch Ball # 19256
    view full answer...

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Info for this part was:

Expert Research:
Michael H
Expert Research:
Lori W
Updated by:
Laura H
Updated by:
Sarah W
Updated by:
Alexander C
Updated by:
Isabelle B

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