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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 # 118730
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Tekonsha Custom Fit Vehicle Wiring - 118730
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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 118730 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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  • Reviews (33)
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Tekonsha Custom Fit Vehicle Wiring - 118730

  • 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 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 inside your rear cargo area, on both the driver's side and passenger's side. You will have to remove the rear threshold and 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 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.

118730 Tekonsha T-1 T-Connector - 4 Wire - Modu-Lite Converter Included

Installation Details 118730 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 - 118730

Average Customer Rating:  4.7 out of 5 stars   (33 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.

2016 Volkswagen Golf

This wiring harness is well built and works well on my 2016 Golf Sportwagen. I’m giving it a 4 star because the installation instructions are not very clear about how to loosen the interior trim panels and actually route the wiring. The harness is great in that to connect to the GSW wiring, you simply need to unplug the GSW wiring connector from the tail lights and plug them into a connector on the trailer wiring harness. You then plug the trailer harness wiring connector to the taillight connector. Note that to unplug the GSW connector from the taillights, you need to move the red locking device back (away from the taillight) before you are able to push down a tab and unplug.
To install remove the rear floor and the trunk divider panels below the floor, then remove the spare tire and the spare tire holder. The spare tire holder can be rotated counterclockwise 90 degrees and pulled up. Then remove the trunk liner in the very bottom. This is pretty straightforward. The rear plastic trunk threshold cover is clipped in place – there are no torx screws or anything else that needs to be removed. To remove it start on one side and pull up and then work your way across till all clips are free.
Now remove the small trim panels on each side just ahead of the taillights. At this point I was still unsure how to loosen the side trim panels to route the wiring from the left side to the right. I removed the torx screw under the rear seat latch and then pulled on the trim panels. They are attached by at least two clips. I was not able to get them all the way free but getting these two clips free gave me just enough room to fish the wires through. It was definitely a tight fit.
At this point per the instructions you are to run a power cable under the car to the battery. I really did not want to do this and I saw that there was a 12V power outlet on the right side. I was able to connect the power to this outlet by splicing into the outlet feeder wire. I disconnected the outlet connector from the outlet by unscrewing a small torx screw in the outlet which freed the connector from the outlet. I was then able to reach down and pull the connector up through the loosened trim panel and the side of the car. Note that there was not much slack and very little clearance to actually reach down to reconnect so disconnect at your own risk. My final step was to change the 12V outlet to be always on rather than to only have power when the car is on. I was able to do that by moving a 20 amp fuse in the interior fuse box (it has two positions, switched and always on). See the photos for more details.

Thanks for your review and photos, Matt. We appreciate your business. We strongly recommend running the 12 volt power wire from this wiring harness directly to the vehicle battery. The 12 volt accessory circuit was not designed to support the additional load of a trailer wiring harness. A wiring harness must have its own dedicated circuit directly to the battery. We have seen many instances where customers have tapped into a 12 volt accessory circuit, like a car lighter socket, and the harness failed. We have also seen instances where the accessory circuit on the car failed in addition to the trailer wiring harness. Also, this will typically void warranties both with the wiring harness and on the vehicle. We understand that running the 12 volt power wire can be a more time consuming task, so we wrote a help article on tips for running this power wire. I have attached the article for you to check out. Be sure to avoid any moving components such as suspension or steering. You will also want to avoid any areas that get excessively hot.
-- Etrailer Expert Laura E - 08/21/2017


Thanks etrailer. You’re the best.
trailer hitch went on without a ....hitch.
The wiring was super easy, with the help of a floor jack, and a headlight, I was able to install each in less than 2hours.
If I have one complaint, sell the wiring with the hitch.
I ordered and installed the trailer hitch not realizing that the wiring would be easier done at the same time.
I was able to run wiring without remove if bumper though, so all is good.


Package was missing most parts. Looked like a repackaged return. I managed to get it to work, but I had to buy some hardware that was supposed to be included.

Customer Service will reach out to you.
-- Etrailer Expert Sierra K - 05/09/2022

2017 Volkswagen Golf Alltrack

Everything was a direct plug & play fit on my 2017 Golf Alltrack. Components seem sturdy and all fit securely in place. Exactly what I would want and expect in an aftermarket wiring harness.

No issues, works as intended!
Daniel - 08/30/2021


I found a small popup I could pull with my VW Alltrack. This harness allowed me to safely (fused) add a 4-pin trailer harness to run the trailer lights. The hardest part is the main 12v feed up to the battery. I've done this previously through a car interior, but decided to go under the car this time. The alltrack has a pretty long underbody 'tray' held up by 4 10mm nuts which took care of much of the run. Other than that it was a matter of avoiding the 4WD (moving) parts and the dual exhaust (hot) parts and securing it with the supplied zipties. Connecting into the care tail lights is trivial since this harness plugs right in (between the car harness and the tail lights). The whole process took me an hour or so - most of which was jacking up the car and deciding how to route that 12v feed up to the engine bay. [I was able to complete the install with the car in the position shown in the picture.]


Great quality with no problems installing or using.


Overall very good installation, not exactly plug and play though if you want the trailer hitch wiring to work.


etrailer is the place to go for hard-to-find products. Their service is excellent and the wiring harness I got works great.

It still works fine. Thanks
Ahop - 07/17/2018


I didn’t know what to buy, I just knew my objectives. I looked through your products which was made easier by the ‘shop by vehicle’ tool (which seemed to know more about accessories for my car than the dealer does). Once I found what I thought would be a good option because it met my objectives including quality and price range, I sent an email through the site email asking all the questions I had. I received an immediate response letting me know my questions had been received and I would receive a detailed email by an associate in the next few days. It was well worth waiting for because the associate was extremely knowledgeable. He answered my questions and then some and in the same email sent me links to be able to purchase exactly what I needed. I ordered a tow package including wiring and a bike rack for a two inch hitch. I took the tow kit to a professional installer and it only took him two hours to install it. He made several comments about the quality of the technology and thanked me for having absolutely everything he needed for the install . The wiring harness and every single nut and bolt!!!!! My husband put the bike rack together at home. Once again the product was so well built and had everything we needed including a nice wrench!!! LOL! We haven’ t taken it on the road yet, but having always had roof racks for our bikes, and now this awesome hitch rack, My husband and I know how much better we did for ourselves by shopping at etrailer. Great online service, excellent product technology, fair pricing, quick shipping, incredible packaging with no styrofoam and almost entirely just cardboard, easy instructions. And to top it off!!!! I can take my own bike on and off the rack without any help!!!!! Thanks etrailer!

2017 Volkswagen Golf SportWagen

Easy install to the lights on both sides. I decided to make my connection temporary and used a 12V plug adapter to power the trailer connector only when needed. I coiled up the wires and stuck them above the jack area and it seems to work perfectly for the few times a year I may use the hitch for pulling a trailer.


VERY Pleased. I wiring harness box was delivered and I installed it in less than 20 minutes.

This is my second wiring harness. I did not need all the learning time to make it work. I had a 12 V cigarette lighter in the back corner of the car which I was able to plug the equipment into. Using my plug-in cord. I did not need to run the wire to the battery.


Well done and with helpful instructions. It does take some mechanical ability, but is doable.


This Wiring harness works great and installed very easy



2017 Volkswagen Golf

Trailer hitch for 2017 golf wagon fit perfect. Instructions where easy to follow and pretty strait forward.
Was able to do it without breaking the plastic rear bumper piece by following the included instructions.

Still works and looks great. Looks like factory install and works like desired.
Donald D - 07/30/2020


The kit was exactly what I saw in the picture and the description. Website is very professional and customer service follow-up was on point!!!! Very happy with the service! Hitch installed very easy along with the wiring harness kit.


Install was ok, the one pain is the power wire that’s supposed to run all the way to the battery, I took a shortcut and wired it to the accessory port that located in the back. Everything works as expected.


The trailer wiring harness for my VW Sportwagen has worked flawlessly and was easy to install. These folks really have the details dialed in and I'll be sure to order from them again in the future.


Looked like a good unit. The issue we had was connecting the power cord to the battery on our VW Jetta. Going through the firewall looked like a bear of a job, so we chalked it up to our inexperience.


Super fast shipping, exactly what I ordered, thanks!


This harness is awesome. I've installed several towing harnesses in the past and this was by far the easiest one I've ever done. Plug and play. Definitely recommend.

2017 Volkswagen Golf SportWagen

The harness works as advertised and fit my VW Sportwagen perfectly, but I'd recommend having a mechanic install it, due to the need to run a wire to the battery terminals at the front of the car (putting the car on a lift makes that job a lot easier!).


The trailer hitch and wiring are working perfectly on my 2017 VW AllTrack - thank you!


works as intended. very easy installation. had several of these on different cars and they are always consistently reliable.


The booster for supplimentary direction lights are good.


Easy install,no splicing plug and play comes with everything needed. Highly recommended.

Show More Reviews

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

  • Will the T-One Vehicle Wiring Harness 118730 Fit a 2019 VW Golf Alltrack with LEDs
    I checked with Tekonsha and the T-One Vehicle Wiring Harness part # 118730 is listed as a fit for all models of a 2019 Volkswagen Golf Alltrack so the LED will not be a problem.
    view full answer...
  • Recommended Trailer Wiring Harness for 2016 Volkswagen Golf Sportswagen
    The T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118730 is made specifically to work with your vehicle's components and the only confirmed fit we have for your vehicle. It does have a power draw directly from the battery as you stated so that it can have the power it needs to function correctly without causing issue to your factory electrical system. It has a ModuLite power module that ensures that you get the correct amperage to each circuit as your tail lights require...
    view full answer...
  • Why Does Trailer Wiring for 2017 Volkswagen Golf SportWagen Come Out of Rear Hatch
    Having the 4-way run out of the back hatch is actually the preferred method although it seems like it wouldn't be. Having the 4-way stored inside the cab of the keeps it protected from rain and moisture to prevent corrosion and keeps it protected from damage to the wiring or connector by rocks or debris that might be on the highway. You can run the wire through the vehicle if you wish but just keep in mind that this does take more time and you may end up needing additional wire because...
    view full answer...
  • Brake Lights on Trailer Not Working With 2017 VW Golf SportWagen
    While we do not have a table, we do have some diagrams in the help articles I linked on trailer wiring and wiring troubleshooting which I recommend taking a look at. And even though your 2017 VW Golf SportWagen has brake lights and turn signals on the same circuit, a 4-way with a powered modulite can still have issues. I recommend first start by checking your grounds to ensure they are securely attached to a bare metal surface free from any type of corrosion, dirt or paint; a bad ground...
    view full answer...
  • 4-Pole Trailer Wiring Harness for 2018 Volkswagen Alltrack with LED Lighting
    The Tekonsha 4-pole wiring harness kit # 118730 is a confirmed fit on the VW Golf Alltrack through model year 2017. For the 2018 model year Tekonsha recommends their ZCI Zero Contact kit # 119250KIT which uses special clamp-on magnetic sensors to detect the vehicle's LED lighting signals. You need make neither cuts nor splices into the car's wiring to install this and it can be easily moved to another vehicle in the future since it is a universal-fit product. Like the harness # 118730...
    view full answer...
  • Trailer Wiring Harness for Canadian 2017 Volkswagen Golf SportWagen
    I do have a solution for you but I cannot confirm that wiring harness # 118730 will work with the Canadian 2017 Volkswagen Golf SportWagen. What you can use is a hardwire harness that is compatible with multi-plex and pulse width modulation wiring systems such as # 119190KIT.
    view full answer...
  • Recommended Trailer Wiring Harness for a 08 Subaru Outback and 17 VW Alltrack
    Over the years we have found that Tekonsha brand wiring harnesses have the best quality. For your 2008 Subaru Outback Wagon, I recommend the T-One Vehicle Wiring Harness part # 118461 as long as you do not have the sport model. For your 2017 Volkswagen Golf Alltrack, I recommend the T-One Vehicle Wiring Harness part # 118730. Both of the above harnesses are almost entirely plug and play. If you need help with installation on your 2008 Subaru Outback Wagon then you can reference the video...
    view full answer...
  • Trailer Wiring Compatible With 2017 VW Golf Hatchback
    On your 2017 VW Golf hatchback, we don't have a custom fit for your vehicle. The other custom fits for other models are not confirmed to fit your Golf hatchback. The wiring harness I recommend for you is the ZCI Circuit Protected Vehicle Wiring Harness w/ 4-Pole Flat Trailer Connector and Installation Kit, # 119250KIT. This will not plug into your wiring with quick connects but will actually connect over your wiring without cutting into it. This harness has zero contact interface sensors...
    view full answer...
  • Troubleshooting Trailer Brake Lights Not Functioning on Tekonsha Harness for 2018 Volkswagen Golf
    First thing you should do at this point is test the 4-way of the wiring harness with a circuit tester part # PTW2993 for voltage on all of the right pins when the taillight signals are being applied. Just like in the video I attached. If the voltage checks out there but the trailer lights still don't function right then the problem is on the trailer wiring. That would mean that problem is either due to a ground issue or a short issue. Make sure that the trailer side connector are clean...
    view full answer...
  • Suggested Installation Time For Curt Trailer Hitch Receiver On a 2016 VW Golf SportWagen
    The Curt Trailer Hitch Receiver # C11422 we have given a installation rating of 2 hours for a DIY installation on your 2016 Volkswagen Golf SportWagen, that will have the capability of a 2nd person to help with the installation at times when a 2nd set of hands is suggested. These are general times given as there will be those that take longer and those that it takes longer to complete the installation. I suggest watching our installation video below to help familiarize yourself with the...
    view full answer...
  • Will Tekonsha ZCI Zero Contact Harness Work on 2019 VW Golf Alltrack
    Yes, the Tekonsha ZCI Circuit Protected Vehicle Wiring Harness # 119250KIT that you referenced will work perfectly to provide you with the necessary 4-Way harness to connect with and power your trailer's signal lights. This is really a great option for your VW Alltrack that features sensitive factory wiring, since it uses unique zero-contact sensors that actually identify current flowing through each wire without having to actually cut into them. I have attached the written installation...
    view full answer...
  • What is the Correct Tekonsha Wiring Harness for a 2015 Volkswagen Golf SportWagen
    I took a look at the answer pages that you were referring to and you are correct that the T-One # 118646 was recommended. It is no longer a fit for the 2015 Volkswagen Golf SportWagen and those questions were completed before a statement came from Tekonsha stating that it won't fit the 2015. I have sent an update for those answer pages to change, thank you for helping us out with that. The T-One # 118730 that you mentioned is a fit for all models of the 2016 Volkswagen SportWagen and the...
    view full answer...
  • Testing Tail Light Wires to Install ZCI Trailer Wiring Harness on a 2018 Volkswagen Golf Alltrack
    While I do not know the wire colors/functions on your 2018 Volkswagen Golf Alltrack I can tell you how to figure it out. Use the included circuit tester that came with the ZCI harness # 119250KIT or if you need one you can get # 40376 to test the tail light wires while someone sits in the vehicle and goes through the various light functions. If there is one wire that has brake lights, tail lights, and turn signals on it then you only use one connector per side on the ZCI harness. You...
    view full answer...
  • Custom Fit Wiring Harness Kit 118730 for 2017 Volkswagen Golf SportWagen
    The custom-fit plastic connectors on wiring harnesses like # 118646 (which fits the 2013 Volkswagen Passat) and # 118730 (which fits the 2017 Volkswagen Golf SportWagen) are not offered as separate parts, sorry to say. Since your existing wiring harness kit # 119190KIT is a hardwired type I understand why you'd prefer not to have to cut into the new vehicle's wiring, but for that you'll need kit # 118730 for the SportWagen.
    view full answer...
  • Parts Needed To Tow a Trailer With a 2017 Volkswagen Golf Alltrack
    The towing package for a vehicle will generally consist of a trailer hitch and trailer wiring harness. As you mentioned, the 2" receiver tube will be a far more versatile option in regards to both towing and hitch mounted accessories like a bike rack. The only trailer hitch with a 2" receiver tube that is offered for your 2017 Volkswagen Golf Alltrack is the EcoHitch Hidden Trailer Hitch Receiver part # 306-X7315. That said, the EcoHitch is in my eyes one of the best on the market because...
    view full answer...
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  • Trailer Hitch and Wiring for a 2017 Volkswagen Golf SportWagen Alltrack
    The Alltrack is a version of the 2017 Volkswagen Golf SportWagen. Curt and Draw-Tite indicate that their hitches fit all models of the 2017 SportWagen. So I recommend Draw-Tite hitch # 24949 since it does not have special requirements for using a bike rack or cargo carrier like the Curt hitch does. The recommended ball mount for this hitch is # 3590. For a 1-7/8 inch ball use # 19257 and for a 2 inch use # 19258. The trailer wiring harness # 118730 is also listed as a fit for all models...
    view full answer...
  • Trailer Hitch and Wiring for a 2017 Volkswagen Golf Alltrack
    Trailer hitch # 24949 is a fit for the 2017 Volkswagen Golf Alltrack. It also is listed for all models of the 2017 Golf Sportwagen. I have included a link to the installation instructions for you. If you plan on doing some towing the recommended ball mount is # 3590. For a 1-7/8 inch ball use # 19257 and for a 2 inch ball use # 19258. And for trailer wiring you can use # 118730 to add a 4-Way flat to the rear of the vehicle. If you want to use the hitch for an accessory such as a bike...
    view full answer...
  • Recommended Trailer Hitch Receiver, Wiring, and Ball Mount For 2017 VW Golf SportWagen
    For your 2017 Volkswagen Golf SportWagen, I recommend the Curt Trailer Hitch Receiver Class I - 1-1/4", # C11422. This is a confirmed fit for your vehicle and works great for light duty towing like you are referring to. You will also need a ball mount to go with your hitch receiver, and I recommend the Curt Class II Drawbar - 2-5/8" Rise, 3-1/4" Drop - 7-1/4" Long - 3,500 lbs, # C45521. This ball mount will require a 1-7/8 inch hitch ball like # 19256 or a 2 inch ball like # 19258. For...
    view full answer...

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Info for this part was:

Employee Lindsey S
Edited by:
Lindsey S
Employee Michael H
Expert Research:
Michael H
Employee Jameson C
Expert Research:
Jameson C
Employee Adam R
Expert Research:
Adam R
Employee Joshua S
Video Edited:
Joshua S
Employee Cole B
Installed by:
Cole B
Employee Chris R
Video by:
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Employee Wilson B
Updated by:
Wilson B
Employee Isabelle B
Updated by:
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Written by:
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Employee Clayton O
Test Fit:
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