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

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

Item # 118449
Our Price: $66.08
You Save: 14%
Custom Fit Vehicle Wiring

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Shipping Weight: 0.85 lbs
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Custom Fit Vehicle Wiring 118449 - 4 Flat - Tekonsha
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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 - no cutting, splicing or tapping required. Powered ModuLite reduces strain on wiring system. 1-800-940-8924 to order Tekonsha custom fit vehicle wiring part number 118449 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.
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  • Reviews (874)
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Tekonsha Custom Fit Vehicle Wiring - 118449

  • Custom Fit
  • Trailer Hitch Wiring
  • 4 Flat
  • 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 - no cutting, splicing or tapping required. 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 - no cutting or splicing of wires
  • 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

Installation on 2014 and 2015 Toyota Highlander

2014-15 Toyota Highlander connection points

This custom-fit T-One connector plugs into your vehicle's wiring harness. The connection points for the 4-way tow harness and the ModuLite (converter) are located underneath the spare tire compartment. Once you've plugged in the ModuLite, locate the "towing fuse" position in your fuse box and insert the included 10-amp fuse.

Installation on 2013 and Earlier Toyota Highlander

This custom-fit T-One connector plugs into your vehicle's wiring harness. The connection point for the 4-way tow harness is located behind the driver's-side interior trim panel in your rear cargo area. The ModuLite plugs into the factory wiring harness beneath your dash, on the driver's side. Once you've plugged in the ModuLite, locate the "towing fuse" position in your fuse box and insert the included 10-amp fuse.

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

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.

118449 Tow Ready T-1 T-Connector - 4 Wire - Modu-Lite

Installation Details 118449 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 - 118449

Average Customer Rating:  4.9 out of 5 stars   (874 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 - no cutting, splicing or tapping required. Powered ModuLite reduces strain on wiring system.


This converter box with wire and pigtail is exactly what I needed for my factory prepped 2012 Toyota Highlander. It did not come with these wires in it. After talking to the folks are etrailer; they squared me away and I got this installed and ready to tow my boat to go fishing. It even comes with the two fuses needed. He spiked mini one for the inline fuse holder as well as the low profile 10 amp fuse for under the hood. I did cut the love off of the pigtail fuse so it would fit into the hole in the compartment in the back by the tail light. I attached my converter box to an existing bolt under the dash against the firewall. It does not weigh that much so all is good. Did not even need to use zip ties just tucked up the firm wires above others and holds well.



Works flawlessly easy install and fit up.

2019 Toyota Highlander

Super easy install. I don't tow a trailer that much, so as per the install video, I left it in the cargo space inside the vehicle. Keeps the wiring and plug clean and out of the elements. Only takes 10 seconds to pull it out and plug in the trailer when needed. Nice product.


Great hitch!! Relatively easy to install and at a great savings over what you would pay at the dealership. I just pull a utility trailer and don't need electric brakes. I bought the electrical kit that allowed me to connect to the factory wiring with no cutting/splicing. I saw a Youtube video in which a fellow used a floor jack with the hitch connected with Vicegrip pliers and used that example to install by myself.

Completely satisfied with the Draw-Tite hitch and

Terry C.


Everything working fine, still completely satisfied with this purchase.


Install and verify only took 30 minutes.
did previously look at video on how to remove parts to get access to factory connections.
Plug and play- excellent!

2019 Toyota Highlander

Easy installation following the video i nstructions.


This by far the easiest wiring harness I’ve ever installed! And a perfect fit.



Still works like the day it was installed we’ve gone many mile since installation works great


First of all this hitch was extremely well priced. The hitch and wiring harness were delivered in the time promised. The hitch fir as promised. I will definitely do business with them again


Tekonsha wiring products can't be beat for performance and durability. They're our "go to" for wiring and we've been installing them for our customers since 1989!

Toyota Highlander

Installation could not have been easier. The video on the e-trailer website for installation in the Highlander was a great help. Even though the vehicle came with the factory tow-prep package that includes a wiring harness, the T-One harness or equivalent is still required. Go figure. As an earlier reviewer noted, with the third-row seat it is necessary to remove the driver-side flip-up third-row cover (the piece just ahead of the tool kit cover). Easy enough to do by simply laying down the rear seat and prying up the rear edge of the cover to loosen the clips. See the attached photos, the first with the cover in place, and the second with it removed. It is necessary to remove this cover to permit removal of the left-side tray to gain access to the existing harness and plug.
One other piece of advice is to thoroughly clean the surface to which the box will be mounted to assure a strong bond with the included two-sided tape. I used alcohol-soaked gauze.
The price through e-trailer was the best I could find anywhere, and the service was second-to-none!

2016 Toyota Highlander

Everything was great. The only thing I was missing for some reason was a 10 amp fuse, but that was easy to replace. It works great!



works great!

2016 Toyota Highlander

To say that the instructions were perfect and the installation was 5 times easier than I thought would still be an understatement. Very easy installation in a 2016 Highlander; anyone with basic skills can do this with professional results. 30 minutes job if you are slow like me.

The only tools you will need are a 10mm wrench or socket, and an auto trim removal tool for popping up the carpet from the rear tray. No wires to cut, or splicing; very clean plugs to connect with built-in plugs already in Highlander. Too easy!


The install of the wiring kit was a breeze. I just watched the video etrailor posted. It was great, no problems or issues. Great Video!!!

2011 Toyota Highlander

Great product. Easy to install (2011 Highlander SE). Fit perfectly. I ran my wiring thru the rubber grommet under the left tray and then under the chassis as described in another customer's review (my pic is prior to sealing the cut with silicone). The product's instruction sheet was good but pics a bit hard to see clearly.'s videos really helped. Disclaimer: the wire routing described is not spec'd by the mfr. in the instructions. It's only an option for you if you choose.


2011 HL, bought OEM hitch and this wiring harness. Pre-wired under dash was just a direct plug-in. Not sure the double sided tape will hold. Getting the plastic tray out of back was a little difficult. Easy plug-in once I got it out. Decided to just leave the plug and wires in the storage bin but could not find a way to route it into the black storage bin without creating a larger hole. I used a Dremel and expanded one hole (see picture). Probably an easier way.


Very easy to install. The installation video was spot on. I cut an access hole to route the harness directly into the cubby hole.


This is the third time I have purchased a trailer hitch from etrailer in the last 8 years. Great experience each time! Very good instructions included. Plus excellent videos on YouTube! Almost forgot, the plug in light wiring kits are simple to install and work great!

2011 Toyota Highlander

Installed on a 2011 Toyota Highlander Base Model

Although the instructions missed some parts on my 3rd row seating model, they were very readable and the installation went quickly. I'll only point out a few things I saw that strayed from the written word, and something that I "modified" for your consideration. I hope this is not considered something that would affect safety/warranty.

Under the dash, the converter box has sticky tape. I couldn't find anything that this would stick to (it just came off once stuck), so I just zip tied it in place.

In the back, there are no instructions on how to remove the "folding cover" for the third row seat. I ended up just pulling it out, which probably wasn't the best. I got lucky, and none of the blind fasteners broke off. Once this folding cover is removed, there's a sticky "tab" that goes over the box over the trailer lighting connector. It's straight forward enough, but not explicitly mentioned.

I did not like the idea of the 4 way flat sticking out the back door. Maybe it would be okay for occasional use, but I'd rather have it under the vehicle. Plus, I use a lighted hitch cover that would not work well if the wire went out the door. Under the tray that is removed to access the trailer connector, there is a large drain/access plug in the steel floor. I removed this plug, then used a sharp utility knife to X out the center of the rubber plug. I only cut enough out to allow the vehicle connector (not the trailer connector, which is larger) to be pushed through; up from the bottom. I replaced the plug in the vehicle, then routed the wires along a factory harness to the connector. I filled the rubber plug with silicone to stop water and fumes from entering the cabin, then replaced all the interior bins and covers.

Under the car, the wiring set is just long enough to reach the hitch. Here I have it plugged into a lighted hitch cover. I keep a 4 foot 4 way flat extension in the vehicle with the draw bar for when I'm towing.

Overall, I'm very satisfied with and their products. Not everything goes to plan, but the products themselves are very good. The price of this DIY job was 1/3 of the cost that the dealer wanted, and I know it was done right. I will buy from them again.

(In the pic, the hitch wiring lights up my hitch cover, which I didn't buy from, but had from a previous vehicle).


This was pretty idiot proof to install on my 2010 highlander hybrid


Everything was installed as instructed, and we didn't run into any surprises, although the video and other illustrations will instruct you to hang the plug out the back door, i dint like that cheesy look so i ran the wire through a drain grommet that is already in the floor on the left side and mounted the 4 prong flat connector to a Mounting Bracket that i attached close to the receiver area for a cleaner more professional look (note the pics was taken prior to the bracket installation) i will update pics later, Item # 18144,

2013 Toyota Highlander

Great standard shipping time was in stock and ordered Saturday received Tuesday. Installed Tuesday night in no time. The only issue is the install of rear Tow-Plug Adapter on Toyota 2013 Highlander Hybrid is different that the pictures in the instructions. In the Toyota 2013 Highlander Hybrid they (Toyota) moved the 12 volt battery into the back driver side compartment, still has the same connector (see picture)

2019 Toyota Highlander

Installed on 2019 Highlander AWD XLE. Installation was very simple. Watch the install video as it will walk you through simple installation. I chose to route the trailer plug through the plugged hole located driver side rear floor deck.


Very very simple install! I ran the trailer wire through the rubber Grommet so that it would be on the exterior underneath the vehicle. Then used some zip ties to secure to lower valance on the vehicle gives it a finished look.


Everything was as described and installation was a snap. Shipping was incredibly fast! Thanks.

2017 Toyota Highlander

This was a very complete kit. Excellent instructions. I had to find a video on the internet on exactly how to remove the toolkit tray from the back of my 2017 Highlander. Once I saw someone pop off those 7 snaps and yank out that small tray on the driver's side, it was easy after that.

2012 Toyota Highlander

This wiring harness is as it says...custom fit for the 2012 Highlander. It was very easy to install and user friendly. Thanks E-Trailer!
Looks great with the Toyota factory hitch.

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