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  1. Custom Fit Vehicle Wiring
  2. Tekonsha
  3. Custom Fit
  4. Trailer Hitch Wiring
  5. 4 Flat
  6. Powered Converter
THIS ITEM IS NOT A FIT FOR
2022 Chevrolet Silverado 3500

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

Item # 118790
Retail:$62.57
Our Price: $47.36
You Save: 24%
Custom Fit Vehicle Wiring
Not Confirmed to Fit

2022 Chevrolet Silverado 3500

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T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector Custom Fit 118790
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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. 1-800-940-8924 to order Tekonsha custom fit vehicle wiring part number 118790 or order online at etrailer.com. 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 (112)
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Tekonsha Custom Fit Vehicle Wiring - 118790

  • 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.


Features:

  • 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 point in rear cargo area
    • Plug in T-connector
  • 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


Specs:

  • Maximum amperage:
    • Stop/turn lights: 5 amps per circuit
    • Tail lights: 7.5 amps per circuit
  • 1-Year limited warranty


Installation

This custom-fit T-One connector plugs into your vehicle's wiring harness, which is located inside your trunk, behind the rear interior trim panel on the driver's side of the rear cargo area. You will need to remove access panels, threshold, trunk floor panels, and trays to access the harness. Once you've plugged in the T-connector, pull back the interior trim panel on the driver's side and locate the ground stud. Loosen the bolt, place the screw eyelet on the stud and re-tighten the bolt.


Once installation is complete, the 4-way flat 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 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.



118790 Tow Ready T-1 T-Connector - 4 Wire - Modu-Lite

Installation Details 118790 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 - 118790

Average Customer Rating:  4.9 out of 5 stars   (112 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.

by:

The product had all the necessary instructions and parts to make the installation very easy. The harness is very simple to use.



by:

All parts arrived in a speedy manner and in great condition! Big thank you to Brent J for all his hard work and extremely fantastic customer service!! Easy to follow install videos for tow hitch and electrical components. Thanks etrailer Team!!



by:

Solid product. Very clear and accurate installation instructions customized exactly to my specific vehicle year and model.



by:
2019 Subaru Ascent

Fit perfect and the DIY video was spot on

Sean

1/10/2024

Still working without issue



by:

Easy install. Bought this with the Curt Class III hitch. All components match up and install without a struggle. The Tekonskha Custom Fit harness incorporates turn signals, running lights and brake lights.



by:
2022 Subaru Ascent

Very easy installation, I followed the video online and got it down very quickly.
Great instructions and installation!

Steven

4/21/2023

It’s been a year already?!, time flies and it works great! Doing some remodeling and had to hook up my old harbor freight trailer to haul the deconstructed 10x20 shed to the dump. Wiring was fine!



by:
Subaru

This worked well on my 2020 Subaru Ascent. The only reason for 4 stars instead of 5 is due to there not being a clamp or something to hold the final cable in place. It isn’t a big deal, you can tuck it into the bumper and that seems to be fine but would have liked a better setup there. Overall great harness and pretty easy to install.

Beau

2/23/2023

Been great over the past year. Used it on a few different trailers and uhauls. No issue and the harness hasn’t fallen out so no issue there



by:

Best experience I have ever had buying car parts! Sales person (Melissa) was competent Delivery was 2 days (a day ahead of schedule), instructional videos were concise and clear. Trailer hitch and harness were well made and fit perfectly. Installed cost was less that a fourth of OEM quote.



by:
2020 Subaru Ascent

This harness was super easy to install and run down through the grommet to the hitch for easy access. I ended up adding some plastic wire loom for protection under the car but was highly satisfied with all of the components in the kit. Watch the video clip for some tips and order with confidence!



by:
2021 Subaru Ascent

Received my order in a timely manner. Very pleased with the hitch and wiring. Installation went smooth due in part to excellent videos.



by:
2019 Subaru Ascent

Super simple to install, and the video was very specific to my vehicle.



by:

Etrailer had what I needed a good price and came a day earlier



by:
Subaru

I purchased this for my 2019 Subaru Ascent along with a Drawtite hitch 76253 and a brake controller with a dash mounted control knob so that the actual controller is hidden near the steering wheel shaft hidden under the dash. All three items were installed and we enjoyed a great summer of RV trailer camping in the summer of 2019.

John

5/1/2021

I had an RV service professional install it because I am too claustrophobic under my Ascent and I am very happy that it is hidden behind with only the control button visible and it works great!



by:

Works perfectly. Easy install.

Benjamin

6/16/2023

No problems, no regrets!



by:

I’m very pleased with the wiring harness and tow bar. Both were very easy to install. It only took about 3 hours and no cutting or drilling was needed. I’d buy again



by:

Super easy to install.

Allyson

5/6/2023

Continues to work great. Really happy with this purchase.



by:
2021 Subaru Ascent

Very simple to install. Instead of letting the wire hang out out of trunk when using like the install video showed I tucked it under the trim and behind the bumper before I put the bumper back on after installing the hitch



by:

Great product. Works perfect and was very easy to install and disappears when not in use.



by:

Arrived quickly with my hitch and, after watching the video (A must!), it installed very easily and quickly with no surprises! This can easily be installed with just the tool needed for attaching the ground wire.

Travis P.

3/30/2020

Great! Required some voltmeter testing to match the right wire to the right harness wire though.



by:

Just what I needed!!



by:
2022 Subaru Ascent

The product works without issue and was easy to install. The reason for 4 stars versus 5 stars is simply the fact it just hangs out your tailgate. There was no mounting options to run it out of sight.



by:

No complaints, easy to install.



by:

Very easy to install. The only difficulty is actually getting to the place where the harness is to be placed. Instructions are easy to follow and, with a little care, the system can be installed with no issues.

Bruce

8/24/2021

Still working very well.



by:

I ordered this item along with the trailer hitch and a bracket. The item was packaged great and arrived in timely fashion. The company was fantastic to work with and service was outstanding.

Finally, the online tutorials on the etrailer website made putting these items in place easy.

I am 150% satisfied with everything this company has done!



by:
2020 Subaru Ascent

I have been using etrailer.com for several years on multiple vehicle hitch and wiring projects and I have always been very pleased with the product and my experience. This time was no different. I needed to install a hitch and wiring harness for a 2020 Subaru Ascent. The parts that were matched with my vehicle online fit perfectly. The instructional videos that accompany every part are outstanding. Each step is clearly explained and easy to follow. Once again, etrailer.com delivered exceptional service, prices, parts, delivery, and everything else I needed to complete my hitch and wiring project in just a few hours. I highly recommend etrailer.com and I will continue to be a customer for several decades to come.


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Show More Reviews

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

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    The Curt # C51180 is compatible with the 2019 Subaru Ascent. If the vehicle has the tow package with the factory 7-way trailer connector, it'll be a plug and play install. If you don't have the factory 7-way, you'll need the # ETBC7L install kit and will need to install a # 118790 4-pole trailer connector. The adapter included with the kit would plug into the 4 pole provided by the # 118790, providing a 7-way. You'd use the wire included in the kit to run a circuit to the positive battery...
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  • 7-Way and 4-Flat Connector for a 2020 Subaru Ascent
    Yes, we do have a wiring harness that has both a 7-way and a 4-way for your 2020 Subaru Ascent. However, you will need a 4-way connector on your car before this will work though. I recommend the Tekonsha T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector item # 118790. This harness plugs in to existing wiring to provide a 4-flat connector. The 7-Way and 4-Way all in one connector you referenced is the Universal Installation Kit for Trailer Brake Controller - 7-Way RV and...
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  • Upgrading 4-Way Harness On a 2020 Subaru Ascent To 7-Way With Trailer Brake Controller
    First you will be able keep the Draw-Tite Max-Frame Trailer Hitch Receiver # 76253 on your 2020 Subaru Ascent. It is rated for up to 750lbs of tongue weight and a trailer weight up to 5,000lbs. Be sure to verify your maximum capacities with your Subaru dealer and do not exceed the lower of the sets of numbers. You will be able to upgrade your trailer wiring from the 4-Way Tekonsha # 118790 to the 7-Way Tekonsha # 118290. You will need to remove the 4-Way Mounting Bracket # 18144 and replace...
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  • Comparing EcoHitch and OEM Hitch to Curt and etrailer Hitches on 2022 Subaru Ascent
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    We've sold quite a few of the etrailer hitch part # e55ZR that fits your 2021 Subaru Ascent and none of our customers have had an issue with the hitch when towing. It was extensively tested and the way it installs is a safe and secure place on the vehicle. There are several other hitches that install the same way for different vehicles and it works fine. I would not worry at all as long as you plan to stay under the weight capacity of the vehicle. For trailer wiring then the Tekonsha kit...
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  • Trailer Hitch Recommendation for 2019 Subaru Ascent
    Yes, for your 2019 Subaru Ascent the Draw Tite hitch part # 76253 is a confirmed fit and would work well for you. It is a 2 inch hitch which is the most popular size and has plenty of towing capacity at 5,00 lb trailer weight. For trailer wiring you'd then want the part # 118790.
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    Yes, the etrailer Trailer Hitch Receiver # e55ZR will fit behind the bumper cover on your 2022 Subaru Ascent. You will also be able to fit either the Tekonsha 4-Way # 118790 or Tekonsha 7-Way # 118290 behind the same panel. You will need the Mounting Brackets # 18140 and # 18144 to secure the 4-way harness or the Mounting Brackets # 18140 and # PK12711U to secure the 7-way connector. I recommend the Tekonsha Prodigy P3 Trailer Brake Controller # 90195 if you need a trailer brake controller...
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  • What is the Difference Between the Draw-Tite 76253 and Curt C25VR for 2020 Subaru Ascent
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  • Hitch Recommendation for 2020 Subaru Ascent that Fits Behind Bumper Panel
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  • Comparing Curt Trailer Hitch C25VR and Draw-Tite 76253 For 2021 Subaru Ascent
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Info for this part was:

Employee Lindsey S
Edited by:
Lindsey S
Employee Jeff D
Installed by:
Jeff D
Employee Joshua S
Video by:
Joshua S
Employee Dustin K
Video by:
Dustin K
Employee Jacob T
Video Edited:
Jacob T
Employee Chris R
Video Edited:
Chris R
Employee Wilson B
Updated by:
Wilson B
Employee Hannah L
Updated by:
Hannah L
Employee Isabelle B
Updated by:
Isabelle B
Employee Alexander C
Written by:
Alexander C
Employee David F
Test Fit:
David F
Employee Ryan G
Test Fit:
Ryan G

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