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  4. Trailer Hitch Wiring
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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 # 118739
Our Price: $67.90
You Save: 28%
Custom Fit Vehicle Wiring

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Tekonsha Trailer Hitch Wiring - 118739
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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. 1-800-496-5010 to order Tekonsha custom fit vehicle wiring part number 118739 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 (76)
  • Q & A (0)
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  • Why etrailer?

Tekonsha Custom Fit Vehicle Wiring - 118739

  • 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 in rear cargo area
    • Plug in T-connector
    • Run hot lead to car 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 inside your rear cargo area, on both the driver's side and passenger's side. You will need to remove the cargo door and some interior paneling to access this 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 in your spare tire compartment.

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.

118739 Tekonsha T-1 T-Connector - 4 Wire - Modu-Lite Converter Included

Replaces Tekonsha 118523

Installation Details 118739 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 - 118739

Average Customer Rating:  4.9 out of 5 stars   (76 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.


The wiring harness is a great quality product, provided with good instructions and everything you need for installation. Connecting the harness to the rear light fixtures is very easy. Running the power supply is a bit tricky once you reach the front driveshaft and steering column (working from the rear of the car toward the battery). There is not much space to get in that section to secure the cable.
The relay tucks away very nicely (see photo) and the cable lengths are perfect.

2017 Volvo XC60

The harness worked perfectly.

2013 Volvo XC60

Haven’t opened up the packaging yet but I always get the proper material so no worries. If I have an issue when the time comes I know I can count on etrailer to make it right.


No problems, easy to have installed and stores stowed away in a panel in the back of the car.


Awesome product. Easy installation.


Easy install, great instructions, everything was provided to install the wiring harness.


Works perfectly and the video made it easy to install.


Arrived quickly, installed in an hour, and it works.


Easy install


Installed on my 2011 XC60 a year ago and it's been working great ever since. Installation is always a little tricky with these things - I used a fuse tap in the rear fuse panel, which is NOT the recommended method, but much cleaner and easier than running a wire.


Install couldn't have been easier. Thanks to the fuse panel located in the driver's side rear access panel, all I needed for the 12v power was the fuse holder, no wire run to the front. Took less that 20 minutes.

2017 Volvo XC60



On time. Fits great. Good instructions.

2016 Volvo XC60

I took my time installing the light kit, dressing all cables and taping them down under the rear panels. The instructions were excellent and easy to follow. I did make two alterations in the installation. First, there was an oval shaped plug at the rear of the car under the spare, so I cut a slit and ran the trailer connector through it to the hitch. The run from the rear of the car to the battery was routed slightly different for example I removed the rear time and routed wire behind wheel well material so no moving suspension parts would damage it. I tested it after installation and everything work perfectly. Used it recently and everything worked. This is an excellent product.

2015 Buick XC60

I purchased and installed a trailer hitch and wiring for my 2015 Volvo XC60. The website is great, easy to use, great products and choices. I required some assistance with my order, called, and their rep Jesse was friendly and very helpful. The kit arrived sooner than expected, intact and well packaged. I've installed a few hitches over the years and this is a great kit, especially the plug-in wiring harness. The hitch installation is a little tricky, you have to remove some parts and fish the mounting bolts into the frame with wires, but the kit is well thought out with all parts provided. The fit is perfect and it looks great. Thank you etrailer - I'll be back!

2017 Volvo XC60

Installed on a 2017 XC60 along with the Draw-Tite hitch... Both fit perfectly, and the installation videos are extremely accurate and helpful. If you plan to install both, my first recommendation is to run the power wire after disconnecting the exhaust hangers from the frame and before installing the hitch. This will give you easy access to the space where the power wire will run in the area behind the rear axle. My second recommendation involves running the power wire near the middle section of the vehicle. In newer models there will be a plastic cover not shown in the video and the heat shield is actually sheet metal in this area. If you disconnect one of the nuts holding the plastic cover (front driver side corner of cover), you can fit your hand in the space and feed the power cable behind the sheet metal heat shield. This also gives you a nice channel to feed the power wire to where the hard lines begin.


The packet arrived as promised with fairly easy to follow instructions. I found more details online at YouTube, which was pretty cool. However, I do NOT suggest running the wiring under the vehicle as suggested. The drilling, wiring, etc. is very very burdensome and I don't think the wire is made for the undercarriage of a car. Instead, I was able to dress the wire through the interior under moldings, carpet etc. and you never see it.
I support etrailer and others can feel safe ordering from them.

2013 Volvo XC60

Just as advertised - Plug and play. Hitch and Wiring Harness were a great combination that fit perfectly! Instructional videos were excellent!

2011 Volvo XC60

The box was basically destroyed on arrival, however nothing was damaged or missing. The hitch for the most part was easy to install, I really liked the routing fish wires supplied for the hidden bolts. Thanks for providing. I used the hitch yesterday and all was fine.

Also, the wiring kit made lights hookup a piece of cake, simple plug and go installation. Thank you.

2010 Volvo XC60

I had in my hands 2 days after I ordered. The installation video was a big help. I am a experienced DIY'er and it took my a good 2 hours just to mount the hitch. I have not tackled the wire harness yet, but should be no problem.
Glad I found Great Prices, Excellent Customer Service and Extremely Fast Shipping! & Installation videos to help you out, how can you go wrong!

2011 Volvo XC60

Quick easy install, the only complaints I have is that the instructions mention the "Red" 12ga power wire which is actually black on my harness. But it's the only 12ga wire so it wasn't confusing. I'll menti that one of my brake lights burned out after about 60 miles of towing but I'm not certain its related.

2010 Volvo XC60

Part fits in about 30 minutes after removing inner floor and satellite navigation CD. Works perfect, using positive feed from fuse box beside right tail light cluster.

Its recommended that the taillight converters power feed be connected directly to the vehicles positive battery terminal as outlined in the installation instructions. Failure to do so could cause damage to the vehicles electrical system.
-- Etrailer Expert Mike L - 05/23/2018

2015 Volvo XC60

Went right in. Instructions and video were perfect. 2015 XC60 has a fuse box right next to the left taillight. Mine had plenty of capacity and open spaces so I wired the 12 volts from there.

One year later and still all good!!
James - 04/21/2019


excellent product, easy to install and like any product from Etrailer, quality and communication is top priority. Whenever I need a trailer product, I don't even look elsewhere, Etrailer is my one-stop website to go...


After a year the trailer wiring kit is still working flawlessly. It seems to be a high quality product, and has very easy to understand instructions. Thanks!!

Show More Reviews

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

  • Does the T-One Harness 118739 Disable Proximity Sensors While in Reverse on a 2012 Volvo XC60
    The T-One Vehicle Wiring Harness part # 118739 which is a fit for your 2012 Volvo XC60 will not shut off the proximity sensors while the trailer is attached and the vehicle is in reverse. The proximity sensors will still work with the wiring harness installed but they would most likely detect the trailer while attached and the vehicle is placed into reverse. This will be the case for all of the aftermarket wiring harnesses we offer for your Volvo XC60. The only trailer wiring harnesses...
    view full answer...
  • Will Tow Ready Wiring Harness 118739 Affect the Trailer Stability Assist on a 2010 Volvo XC60
    Because the Tow Ready wiring harness, # 118739, connects to the tail light wiring for the proper signals and the vehicle battery to power the trailer lights, it will not interfere with the stability assist feature on your 2010 Volvo XC60. The tail light wiring and the stability assist are two separate systems. I have included a link to the installation instructions for you to view.
    view full answer...
  • Can a 12 Volt Outlet Provide Power to a Trailer Wiring Harness on a 2012 Volvo XC60
    The trailer wiring harness # 118739 was only tested and rated for use when connected to the vehicle battery as indicated in the instructions I have linked. You should not use any other power source because it, too, is not rated for this purpose so there is no way to determine how it would operate. Connecting the wire to the battery is not as difficult as you might think. The most time-consuming part is routing the wire. Everything else is fairly straight forward.
    view full answer...
  • 4-Way to 5-Way Flat Trailer Connector Adapter for a 2014 Volvo XC60
    You are correct that wiring harness # 118739 for your 2014 Volvo XC60 does not have a connection for the reverse lights on the vehicle. You will need a 4 to 5-Way flat adapter, # 20036, to convert it to a 5-Way. The only tricky part is locating the reverse light wire on the vehicle. It looks like the reverse lights are in the tail light assemblies (instead of in the hatch) so it should not be all that difficult. All you need to do is find the back of the reverse light and the wire that...
    view full answer...
  • Install Picture of the Curt Trailer Hitch part # 13268
    We haven't had the chance to install the Curt Hitch part # 13268 on a 2014 Volvo XC60R, but we do have some install pictures and a video on a 2011 Volvo XC60 that I attached for you to check out. It will install in the same area on your vehicle and give you the same look. For trailer wiring you would want the Tow Ready harness part # 118739. For ball mounts I recommend the etrailer Ball Mount Kit # 989900. It comes with 2 ball mounts, 2 balls, a hitch pin with clip, and a carrying bag.
    view full answer...
    Image 1 for
  • Trailer Wiring Harness for 2011 Volvo XC60
    The correct trailer wiring harness for your 2011 Volvo XC60 is part # 118739. This wiring harness is vehicle-specific and would be much easier to install than the harness you referenced, which is a more general application. A wiring connector would plug inline behind each of your tail light assemblies, one wire would ground to the vehicle, and a power wire would run under the vehicle to the positive battery terminal using the provided fuse holder.
    view full answer...
  • Trailer Hitch and Wiring Recommendations for a 2014 Volvo XC60
    Whenever there are Class II and Class III trailer hitch options for a vehicle I always recommend going with the Class III for a few reasons. First, the Class III hitch is going to be stronger, more metal, and considering that you are towing a trailer behind the vehicle going with a stronger hitch is a good thing. The other benefit is that a Class III trailer hitch will have a 2 inch receiver opening which is compatible with more accessories than a 1-1/4 inch hitch. But all of the hitches...
    view full answer...
  • Will a Trailer Hitch Receiver Reduce Ground Clearance for a 2015 Volvo XC60
    Unless you have a vehicle that needs the fascia cut out to make room for the receiver, any hitch that is installed on your vehicle will reduce the ground clearance. This is the same case for your 2015 Volvo XC60. I recommend going with the Draw-Tite Max-Frame Trailer Hitch Receiver # 75671 which is a Class III hitch with a 2 inch receiver. It has a Gross Towing Weight (GTW) of 4,000 lbs and a Tongue Weight (TW) of 400 lbs. When used with a Weight Distribution (WD) system those capacities...
    view full answer...
  • Trailer Hitch and Wiring for a 2013 Volvo XC60 R-Design
    The Curt trailer hitch # 13268 does fit the 2013 Volvo XC60. We have the following installation note for the R-Design models: Bumper cover may need to be removed and trimmed for proper hitch installation on R-Design models. I have included a link to the installation instructions for you to view. If you plan on doing some towing I recommend the etrailer ball mount kit # 989900. It comes with 2 ball mounts, 2 balls, a hitch pin and clip, and a storage bag. For trailer wiring use # 118739....
    view full answer...
  • Trailer Hitch and Wiring for a 2011 Volvo XC60
    Exhaust/hitch rattle can occur on any vehicle. It is because the exhaust is never quite in the same place on any two vehicles. But if you happen to have this issue on your 2011 Volvo XC60 then there are some things you can do to correct the problem. I have included a link to a help article on this very issue. All of the trailer hitches for your Volvo have the same design and install in the same places so there isn't one that is less likely to have an issue than any of the others. If you...
    view full answer...
  • Is Trimming Required When Installing Curt Trailer Hitch Receiver 13268 On 2017 Volvo XC60 R-Design
    The Curt Trailer Hitch Receiver - Custom Fit - Class III # 13268 you were looking at is confirmed to fit your 2017 Volvo XC60 R-Design, and may require you to trim the bumper fascia to clear the hitch. You will also need to trim the heatshield slightly, but you will not need to permanently remove anything. All of the hitches for your vehicle will have the same requirements. You may also be interested in a trailer wiring harness # 118739, and a ball mount, hitch ball, and hitch pin and...
    view full answer...
  • Comparison of Tekonsha T-One and Curt T-Connector Wiring Harness for 2017 Volvo XC60
    The # 118739 Tekonsha T-One harness and # C56355 Curt T-Connector harness are both custom fit for the 2017 Volvo XC60. The installation is the same for both. The Curt has a powered converter using SMT and the Tekonsha has a powered ModuLite converter, both are designed to reduce strain on the wiring system. I recommend the Tekonsha over the Curt. Based on feedback from our installers and customers we have found the Tekonsha harness to be the more reliable of the two. I have attached...
    view full answer...
  • Parts Needed to Add 7-Way Trailer Wiring Harness and Electric Brake Controller on a 2011 Volvo XC60
    We can absolutely help you with what you need to install the 7-way trailer connector and brake controller in your 2011 Volvo XC60. To start with you'll need a 4-way trailer connector # 118739. This plugs in behind some paneling in the rear cargo area on both sides. Then the hot lead will need to be run to the positive of the Volvo's battery. Once you have the 4-way use our # ETBC7 kit to convert it to a 7-way. This kit also includes everything to install the brake controller. If you...
    view full answer...
  • Recommended Trailer Hitch And Trailer Wiring For 2012 Volvo XC60
    If you are looking for a video that explains how to install a trailer hitch on a 2012 XC60 I can help you out. The XC60 is the same generation for 2008 and up so the installation for a hitch on your 2012 would be the same for those vehicle. The hitch you came from, part # 13268 is a Class lll hitch from Curt. This is a Class lll hitch and it has a 2 inch receiver opening. I have attached a video for this installation of this hitch on a 2013 XC60 which would be the same as your 2012. If...
    view full answer...
  • Why Does Curt Hitch for 2013 Volvo XC60 List a Harder Install than Draw Tite
    The difficulty ratings for the install of the hitches for the 2013 Volvo XC60 are decided by the manufacturers. The Draw Tite hitch part # 75671 and the Curt part # 13268 are both so similar that neither would install easier than the other. Curt just estimated that their hitch would take around 20 minutes longer than Draw Tite did. The install rating is nothing more than just the length of time it would take. I attached an install video for the Draw Tite for you to check out as well. If...
    view full answer...
  • Recommended Trailer Hitch Receiver, Wiring, and Ball Mount Compatible with 2015.5 Volvo XC60
    The 2015.5 Volvo XC60 leaves a little hubbub as you mentioned over model year fits. You won't need to worry about this as we have the Draw-Tite Max-Frame Trailer Hitch Receiver - Custom Fit - Class III - 2" # 75671 confirmed to fit all 2010 thru 2017 models of the XC60. This hitch does require a specific ball mount size to fit properly. I recommend the Draw-Tite Ball Mount for 2" Hitches - 3/4" Rise, 2" Drop - 8-1/2" Long - 7.5K # 2923 which is a confirmed fit. You will also want a...
    view full answer...
    Image 1 for
  • Different Installation Difficulty Ratings for Hitches for the 2013 Volvo XC60
    The hitch installation difficulty ratings we show for the three hitches specified for your 2013 Volvo XC60 are based on the manufacturer ratings. These are the estimated times required for an experienced professional installer to complete the job. For any hitch, the time needed for a first-time effort will be longer; how much longer will depend to a degree on whether you have access to the tools and equipment resources a professional installer would have, such as a vehicle lift. Both hitches...
    view full answer...
  • Installing Draw-Tite Class III Receiver Part # 75671 Hitch on Volvo XC60
    The Draw-Tite Class III Receiver you mentioned, part # 75671 is a fit for 2010-2017 Volvo XC60 models. Instead of the weld nuts used in the XC90, the XC60 will have holes in the frame (as you have found). To install the hitch, large block washers and carriage bolts are threaded up into the frame so that the bolts stick out of the frame members and provide an attachment point. The hitch includes a fish wire that is used to pass the block washers and bolts into the frame. This procedure...
    view full answer...
  • Fit of Draw-Tite Class III Trailer Hitch on 2010 Volvo XC60
    According to my research, the Volvo was first available in North America as a 2010 model, is it possible your vehicle was manufactured in 2009 as a 2010 model? The Draw-Tite Class III hitch, part # 75671 would indeed be a fit. If your XC60 is a European spec vehicle, the fit of the hitch has NOT been tested, so I wouldn't be able to guarantee fit. If you'll be using the hitch for towing purposes, you'll need the following to complete your towing system: Trailer wiring harness with 4-pole...
    view full answer...
  • Parts Needed to Tow Trailer with 2015 Volvo XC60
    For your 2015 Volvo XC60 I recommend going with the Curt # 13268 hitch because the heavy powder coating that Curt uses on their hitches is going to help protect against rust and corrosion, which will be especially helpful in the wet Florida climate. This will be a great choice for your Volvo XC60 and will provide you with a safe solution for towing your boat. In order to tow a trailer you'll also need a few other things: a wiring harness, ball mount and hitch ball. For a wiring harness...
    view full answer...
  • How Does Hayes Brake Controller install in 2012 Volvo XC60
    You will need to start with a 4-way (if you do not have one) installed on your 2012 Volvo XC60 to install a brake controller. For that you would want the # 118739 which I attached an install video for. From there you would need to convert the 4-way to a 7-way so that you can install the Hayes brake controller # HA81742B. For that you will want the Brake Controller Install Kit and 7-Way Adapter part # ETBC7. I attached installation instructions and an install video for this product as well....
    view full answer...
    Image 1 for
  • Trailer Hitch Receiver and Wiring Harness Warranty For a 2012 Volvo XC60
    The Curt Trailer Hitch Receiver # 13268 that fits your 2012 Volvo XC60 comes with a limited lifetime warranty from Curt. I recommend installing the T-One Vehicle Wiring Harness # 118739 when you install the receiver. This will give you a 4-way flat connector for use with Auxiliary Lights # C53201 on any hitch mounted accessories you may use that impair the view of your tail lights. It can also be used for the lights on most small trailers you may tow. While the harness only comes with...
    view full answer...
  • Trailer Hitch Receiver and 7-Way Connector Compatible With a 2015.5 Volvo XC60
    Currently there is only a 4-Way Flat Connector # 118739 for your 2015.5 Volvo XC60. You will still be able to use this with a Universal Installation Kit for Trailer Brake Controller # ETBC7. The 4-way will connect to the 7-way and give you the wiring and parts needed to install a Redarc Tow-Pro Liberty Brake Controller # RED52VR with the 7-way. These harnesses will not require any special parts or programming from Volvo. The Draw-Tite Max-Frame Trailer Hitch Receiver # 76116 being a class...
    view full answer...
  • How Far Below the Bottom Edge of Bumper Fascia Do Hitches For 2013 Volvo XC60 Extend
    The Draw-Tite # 75671 and Curt # 13268 Class III hitches both feature a durable powder coated finish. As you can see in the accompanying photo I provided, both hitches will have about a 1 inch reveal below the bottom edge of the bumper fascia. Keep in mind that if your XC60 is the R Design model, some fascia trimming might be needed. Both hitches would install in the same manner, and share identical weight capacities. I'd recommend the Curt # 13268 as it's the least expensive. If you'll...
    view full answer...
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Info for this part was:

Employee Lindsey S
Edited by:
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Employee Joshua S
Video Edited:
Joshua S
Employee Jacob T
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Jacob T
Employee Chris R
Video Edited:
Chris R
Employee Cole B
Installed by:
Cole B
Employee Wilson B
Updated by:
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Employee Alexander C
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