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  1. Custom Fit Vehicle Wiring
  2. Tekonsha
  3. Custom Fit
  4. 4 Flat
  5. Trailer Hitch Wiring
  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 # 118401
Our Price: $32.46
You Save: 56%
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 - no cutting, splicing or tapping required. Circuit-protected converter guards against shorts. 1-800-940-8924 to order Tekonsha custom fit vehicle wiring part number 118401 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 (51)
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Tekonsha Custom Fit Vehicle Wiring - 118401

  • Custom Fit
  • 4 Flat
  • Trailer Hitch Wiring
  • Tekonsha
  • 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 - no cutting, splicing or tapping required. Circuit-protected converter guards against shorts.


  • 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
    • Locate connection point at the rear, on the passenger's side
    • Plug in connector
  • Includes circuit-protected tail light converter to ensure that your vehicle's wiring matches that of your trailer
    • Provides protection against electrical shorts and overloads
  • 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 amps per circuit
  • 1-Year limited warranty


This custom-fit T-One connector plugs into your vehicle's wiring harness, which is located at the rear, between the bumper and the tire on the passenger's side.

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 plug on your automobile and the 4-pole connector itself - to help prevent corrosion.

Circuit-Protected Tail Light Converter

A tail light converter 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. The tail light converter combines 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.

This converter safeguards itself and your vehicle against possible electrical shorts and overloads with integrated short circuit protection. Just install the connector as indicated and rest assured that the wiring system of your vehicle will remain feedback-free.

118401 Tow Ready T-1 T-Connector - 4 Wire

Installation Details 118401 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 - 118401

Average Customer Rating:  4.9 out of 5 stars   (51 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. Circuit-protected converter guards against shorts.

by: 01/13/2024

It's been at least two years and I use it several times a month. It hasn't failed yet. It's mounted in an area exposed to harsh conditions...water and mud, even pulling a trailer in the just keeps working.


Exactly what I needed. Delivered a day earlier than expected. Videos showed me exactly how to install. Great service all the way around


This was easy enough to connect to the existing wiring of the vehicle. But the only mounting tab for a screw to go through is in a bad location. This led to a lot of cursing and frustration. Once I got the screw through the control box the mounting tab was flimsy, and I know I will eventually find this dangling from the bottom of my SUV. The control box should have mounting tabs on either side and not on the sides where the wiring comes out. This would allow for a sturdier installation, because the double sided tape they send with the unit is never going to stick to anything under a car that has been in use for a number of years.



So far so good.

2009 Kia Sportage

Even though I have very little mechanical know-how, I was able to install this kit on my 2009 Kia Sportage in about thirty minutes. The kit itself is very simple, and the website has great video tutorials that walked me step by step through the process. (Watching the videos before I ordered the items is what gave the confidence to actually try this, because again, I'm not the most mechanically inclined person in the world. If you need to put an electric hook-up on your car, I highly recommend this set-up from this retailer.
When I decided to go ahead with this project, I was still a little unsure about what I needed, so called the customer service number and spoke to a very friendly young lady who told me exactly what in needed.
If you decide to try this, in addition to this item, pick up the end cap tester with LED lights (part #30512) this will allow you to test the hook-up when you are done without having to hook up to a trailer. Making sure you have a good ground is the most important step, and if after testing with this cap, your setup doesn't work, redo the ground wire in another spot, because this seems to be the thing that screws most people up.
Also order a tube of dielectric grease for all your connections and a mounting bracket (part #18144), otherwise the connection just hangs there and has to be tucked up in the bumper.
As for this retailer, I will definitely be using them again. Customer service was great, the video tutorials they provide make the work easy, they ship quickly, and their prices are very competitive.


Fits great on our 09 kia sportage. Pulls the dirtbike trailer very smoothly.

Install took a little while because I'm a perfectionist and wanted to zip tie the wires away from the exhaust. I needed a couple more zip ties than the wire kit came with. Drilled holes for the 4 pin plug mounting bracket (part # 18144) It looks great. Factory look and will keep the plug from dragging the ground.

Would buy again. Good quality

2006 Kia Sportage

Combined with trailer wiring harness the frame hitch was easy to install in under one hour and makes a functional and attractive addition to my new used 2006 Kia Sportage. Thanks for the speedy delivery. Finished the installation with a rubber hiitch cover and a hitch receiver lock padlock.


I was blowing fuses with my old trailer harness. This was easy to install and fixed the problem!

Etrailer Expert

Shane F.


Product is working well but have needed dielectric grease to keep connections working.


The Etrailer T-One Wiring Harness w/4-pole Trailer Connector is the easiest self contained trailer light harness that exists. Everything you need down to wire ties and double back adhesive tape and online instructions for a neat clean install.

2006 Kia Sportage

My trailer hitch and parts needed came to the house quickly. Very Heavy duty. Assembly went smooth with instructions for my 2006 Kia Sportage. The trailer light harness is spot on, I found one of etrailer's videos on installation for my vehicle. I will be pulling my cargo and small camp trailer very soon.


i found etrailer on utube and it lead me to the website. The installation videos were simple and easy to understand. I installed a hitch and trailer wiring with no problems at all. the staff was helpful as i had a few questions about the wiring harness before the purchase and they helped me out. ETRAILER fan for life
tim petersen

2008 Kia Sportage

Nice product, quick ship, easy install. Hitch was installed in less than an hour on a 2008 Kia sportage. Online video very helpful for both the wiring harness and the hitch. Product was well packaged. Hooking up the boat and goin fishin ...:)

2006 Kia Sportage

The T-One Connector trailer wiring kit that I had ordered arrived several days earlier than anticipated. Ordering was very easy on the web site. The product is a perfect fit for my 2006 Kia Sportage. I look forward to doing business in the future with etrailer.

Kia Sportage

I am so glad I ran across your web site and ordered the receiver hitch and wiring kit. It was not like some others that were generic and would have to be modified, but was an exact fit for my Kia Sportage. The videos made it so I could do the work like a pro!

2008 Kia Sportage

Replaced a prior harness with a new one. Easy Installation and works great. Did learn from prior experience to wrap electrical tape around areas that have a tendency to wear from rubbing on the car frame to provide extra protection prior to installing this one.


Easy to install, everything you need to do it is right in the kit. I would recommend this kit to anyone wiring up a trailer hitch. 15 Minutes is all it takes to completed.

2006 Kia Sportage

Very simple to install. Exactly what I needed. 6 to 12 more in of wire on the hitch side would be a worthy improvement. As is, its just barely long enough. Still worth every penny.


This wire harness is great last one lasted 10 yrs

2008 Kia Sportage

Super easy to install with only one hole to drill. The only complaint I have is that the grounding screw provided was a little small and it broke off during drilling. We utilized a slightly larger one that worked wonders.

2006 Kia Sportage

Quick delivery. Have already installed and out performs the 55529 that was on the Kia Sportage. I am completely satisfied. If I have a problem I know etrailer will be helpful. Satisfied customer.


Great product, fit like it is supposed to. Showed you how to install it right from the web site. I used it to check my KIA before I did the order to make sure it was indeed the right product. Very satisfied!

2009 Kia Sportage

The wire harness was so easy to install since it plugged right into the vehicle wiring. The price was 400% less than the dealer price. Yes, it was 400% less.


Very happy with the quality, and fit!



still think so well of your Company, the precise build of your hitch, and the perfect fit, of the hitch and wiring, shows the high standards, that you have. Totally satisfied!

2009 Kia Sportage

Good service. Fast delivery,quality par t.

John B.


Works great


Bought for my husband who complains about everything. He's not complaining, so I'm happy.


Super easy to install. Only problem was the amount of dirt I had on my cap under the car that connected the 4-pole. Had to take it to a garage to loosen it up. Had nothing to do with the product though...

Show More Reviews

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

  • Recommended Trailer Hitch and Towing Accessories for 2007 Kia Sportage
    The number of cylinders the engine has will have NO bearing on which hitch will fit. Any of the hitches we offer for the 2007 Kia Sportage will fit 4 and 6 cylinder models. Although which engine you have doesn't dictate the hitch used, it will dictate the trailer wiring harness. For the best hitch at the best price point, I'd recommend going with the Curt Class III, part # 13526. If you plan on towing with the hitch, you'll need a few other items to complete your towing system. For trailer...
    view full answer...
  • Class III Trailer Hitch and Wiring for a 2010 Kia Sportage V6
    Curt Class III trailer hitch # 13526 is indeed a fit for your 2010 Kia Sportage V6. Class III hitches like this are great for towing and for hitch mounted accessories like bike racks and cargo carriers. If you plan on doing some towing I recommend etrailer ball mount kit # 989900. It comes with 2 ball mounts; one with a 3/4 inch rise or 2 inch drop and one with a 2-3/4 inch rise or 4 inch drop. It also includes a 1-7/8 inch ball, 2 inch ball, hitch pin with clip, and a storage bag. If...
    view full answer...
  • Is There Any Difference Between Curt C55529 and Tekonsha 111401 For 2008 Kia Sportage V6
    Both the Curt # C55529 and the Tekonsha # 118401 are designed to fit on your 2008 Kia Sportage with the V6 engine; they both have the same functions and provide you with a 4 way plug for towing a trailer with your Sportage. The only difference aside from the manufacturer is that the Curt # C55529 can handle tail lights on the trailer that draw a bit more amperage (3 amps) compared to the Tekonsha # 118401 (2.1 amps); this would be especially helpful when towing a trailer with a lot of lights...
    view full answer...
  • Will Curt Trailer Hitch # 13526 Fit a 2009 Kia Sportage with Dual Exhaust
    Yes, the CURT Trailer Hitch, # 13526, will fit a 2009 Kia Sportage with dual exhaust. If you look at the fourth picture on the product page, you will see the hitch installed on a dual exhaust model. The instructions, linked for reference, also show the hitch using a dual exhaust model as an example. If you plan to do some towing, the recommended ball mount is # AMSC2 and you can use pin and clip # PC3. For a ball, you can use # 19260 (1-7/8 inch diameter), # 19247 (2 inch diameter), or...
    view full answer...
  • Higher Capacity Trailer Hitch Recommendation for a 2010 Kia Sportage
    For your 2010 Kia Sportage the highest towing capacity available is the # 75561 which has a 350 lb tongue weight capacity and a 3,500 lb total trailer weight. Not every vehicle has high capacity hitches available. For lighter duty vehicles there are lighter duty hitches made. It wouldn't really make much sense to put a heavy duty hitch on a vehicle that isn't rated for the same capacities as the hitch. Since you have a 6 cylinder model you would want the part # 118401 for trailer wiring. If...
    view full answer...
  • Recommended Vehicle Wiring Harness For 2010 Kia Sportage That Current Harness Got Melted
    I am sorry to hear that! Based on how damaged the harness you have installed on your 2010 Kia Sportage V6 is due to the heat from the exhaust you would benefit from replacing the entire harness, as the damage in your first picture is pretty severe. I recommend going with the Tekonsha # 118401 and wrapping the harness with some exhaust wrap which you can pick up from your local auto parts store. In addition to that I recommend trying to keep the harness as far away from the exhaust as...
    view full answer...
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  • Replacement Trailer Wiring Harness for 2006 Kia Sportage
    The wiring harness you will need for your 2006 Kia Sportage is # 118401. It will plug directly into the existing wiring of your vehicle. I've attached a video of it being installed on a 2007 Sportage which is the same process as yours.
    view full answer...
  • Kia Dealer Installed Trailer Harness and Is Now Malfunctioning
    I would say either the dealer gave you a bad part, or the wrong part. The yellow wires should be attached to the driver side tail light to supply the driver side blinker signal. The other connector goes over to the passenger side tail light. On the passenger side, the red wire picks up brake light signal, brown wire picks up running/tail lights, green wire is the passenger side turn signal and the white wire is the ground. I imagine the part the dealer installed is something similar to...
    view full answer...
  • Wiring Harness Adapter for a 2007 Kia Sportate
    If you have a 6 cylinder vehicle then the part you selected will work on your vehicle and plug in underneath the passengers side between the spare tire and the bumper. If you have a 4 cylinder vehicle then you will need part # 33925 (that also works on the 6 cylinder) which will hook up in line with and behind the vehicle taillights. Both items include the adapter the mechanic referred to and come with instructions that include pictures for easy installation. If you need further assistance,...
    view full answer...
  • Trailer Wiring Harness Recommendation for a 2007 Kia Sportage 4 Cylinder
    The purpose of trailer wiring harnesses like the part # 118401 that you referenced is to connect your vehicles taillight signals to the trailer lighting so that when your brake lights/turn signals/running lights are activated on your tow vehicle the trailer lights do the same. Since you have a 4 cylinder model 2007 Kia Sportage you would want the part # 119178KIT instead of the # 118401 as it has only been confirmed to fit the 6 cylinder models.
    view full answer...
  • Blowing Fuses on 2009 Kia Sportage Using Tow Ready T-One Wiring Harness # 118401
    As long as the Tow Ready T-One Wiring Harness, part # 118401, is installed correctly on your 2009 Kia Sportage EX V6, which is a simple plug-in connector and ground the white wire installation, and you are getting power to the 4-Way connector, the problem is probably not with the vehicle. To be sure you can disconnect the t-one connectors from the vehicle and check them making sure that there are no bent pins inside the connector causing a short. When you put the connectors back together,...
    view full answer...
  • Parts Needed to Tow a Boat Trailer With a 2008 Kia Sportage
    We have everything that you need to tow a boat trailer with your 2008 Kia Sportage. In addition to the Curt Class III Trailer Hitch, # 13526, that you referenced, you will also need the T-One Vehicle Wiring Harness, # 118401. We have installed this hitch and wiring harness on a 2008 Kia Sportage at our shop so I linked the videos for you to check out. I have also attached the installation instructions. One final item that I would recommend is the Ball Mount Kit, # 989900. This kit includes...
    view full answer...

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