1. Custom Fit Vehicle Wiring
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  3. Custom Fit
  4. Trailer Hitch Wiring
  5. 7 Blade
  6. Powered Converter
Tekonsha OEM Replacement Vehicle Wiring Harness with 7-Way Trailer Connector

Tekonsha OEM Replacement Vehicle Wiring Harness with 7-Way Trailer Connector

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Custom Fit Vehicle Wiring

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Tekonsha Custom Fit Vehicle Wiring - 118290
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Replace the damaged 7-way, RV-style trailer connector on your vehicle with this T-One harness. T-One connector plugs directly into existing wiring - no cutting, splicing or tapping required. ModuLite reduces strain on wiring system. Call 800-298-8924 to order Tekonsha custom fit vehicle wiring part number 118290 or order online at etrailer.com. Free expert support on all Tekonsha products. Guaranteed Lowest Price and Fastest Shipping for Tekonsha OEM Replacement Vehicle Wiring Harness with 7-Way Trailer Connector. Custom Fit Vehicle Wiring reviews from real customers.
  • All Info
  • Reviews (3)
  • Q & A (6)
  • Photos
  • Why etrailer?

Tekonsha Custom Fit Vehicle Wiring

  • Custom Fit
  • Trailer Hitch Wiring
  • Tekonsha
  • 7 Blade
  • Powered Converter

Replace the damaged 7-way, RV-style trailer connector on your vehicle with this T-One harness. T-One connector plugs directly into existing wiring - no cutting, splicing or tapping required. ModuLite reduces strain on wiring system.


  • Wiring harness replaces damaged factory 7-way, blade-style trailer connector at the back of your vehicle
    • Enables your truck to power your trailer's signal lights
    • Compatible with 4-pole, 5-pole, and 6-pole adapters (sold separately)
  • Connects quickly and easily - no cutting or splicing of wires
    • Tow harness with 7-way connector plugs into connection point behind rear interior trim panel
    • ModuLite connects in rear cargo area
  • Supplies required relays and fuses to activate functions
  • Constructed of 16-gauge bonded wire
  • Mounting bracket sold separately


  • Maximum amperage:
    • Stop/turn lights: 4.2 amps per circuit
    • Tail lights: 12 amps per circuit
  • Limited 1-year warranty


This custom-fit T-One connector plugs into your vehicle's wiring harness. You will have to remove access panels, threshold, trunk floor panels and trays, and some interior paneling to access this harness. The connection point for the 7-way tow harness is located behind the rear bumper, on the driver's side. The Modulite plugs into the factory wiring harness within the driver's-side storage compartment in your rear cargo area. Once you've plugged in the Modulite, insert the included fuses and relays into your fuse panel as indicated in the instructions.

Once installation is complete, the 7-way 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 plugs on your automobile and the 7-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.

118290 Tekonsha Replacement Harness for Factory Tow Package - 7 Pole - Modu-Lite

Item # 118290

Installation Details 118290 Installation instructions

This Product Fits The Following Vehicles

California residents: click here

Customer Reviews

Tekonsha OEM Replacement Vehicle Wiring Harness with 7-Way Trailer Connector - 118290

Average Customer Rating:  4.7 out of 5 stars   (3 Customer Reviews)

Replace the damaged 7-way, RV-style trailer connector on your vehicle with this T-One harness. T-One connector plugs directly into existing wiring - no cutting, splicing or tapping required. ModuLite reduces strain on wiring system.

- 118290
2020 Subaru Ascent

Installed in my 2020 Subaru Ascent with no issues. The only thing I didn't do was run the black wire to the battery. All other lights tested okay and will be using it for the first time on the 30th of June. 816639

- 118290
2020 Subaru Ascent

Kit was nice, but the bracket I purchased did not match the 7 pin connector so I had to drill the connector to match the holes. 793099

- 118290
2019 Subaru Ascent

Great hitch, easy to install. The 7-pin wiring harness was a bit more complex but I was able to find a way NOT to drill a new hole in my Subaru. I hope to share what I found with etrailer.com so that they can do a video of it. Shipping was fast and have been impressed with them before and will continue to do business with them in the future. 790357


Ask the Experts about this Tekonsha Custom Fit Vehicle Wiring

  • Troubleshooting No Power to 7 way Plug From Converter on Tekonsha 118290
    The Tekonsha # 118290 is a confirmed fit on the 2020 Subaru Ascent, and it sounds like maybe you're seeing different colors on the wires coming out of your factory harness compared to the one on the on the Tekonsha # 118290 harness. I'll start by saying that the colors aren't always a perfect indicator, so you can use a circuit tester like the # PTW2993 to test the wires going into the harness that you're plugging into to make sure that they're providing power with the appropriate functions...
    view full answer...
  • Advice for Routing Power Wire for Tekonsha Trailer Wiring on 2020 Subaru Ascent
    Basically all of the instructions for trailer wiring like the Tekonsha # 118290 for your 2020 Subaru Ascent are kind of vague when it comes to routing the power wire to the battery which is why we came up with a helpful article on this (see attached). Although it seems like a pain, the easiest way to route the wire is by going under the vehicle. If there are any places where you can run the wire through the frame of your vehicle then do that as it will be the easiest way to avoid damage...
    view full answer...
  • Trailer Running Light Pin Active On a 2019 Subaru Ascent With Vehicle Off
    The running light pin on your trailer connector should not be active while the vehicle is off. If that is not the case then most likely the converter box has failed. For replacement, we have the Tekonsha OEM Replacement Vehicle Wiring Harness part # 118290 which can be converted to a 4 and 7-way trailer connector by adding the 7- and 4-Pole Trailer Connector Socket part # HM40975. The only other option you have is to take your vehicle in for service.
    view full answer...
  • Do I Have to Connect the Black Wire on the 118290 on my 2020 Subaru Ascent
    If all of your signals are working there may be no need to connect the wire that is for the 12 Volt trailer power on the Tekonsha OEM Replacement Vehicle Wiring Harness with 7-Way Trailer Connector part # 118290 but I can not advise you to do anything except what is found in their instructions which states to connect the wire. In some cases not only does this wire power the 12 volt connector but may also be used to power the converter taking the excess strain off of your vehicles wiring harness.
    view full answer...
  • How To Install a 7-Way Trailer Wiring Harness On a 2019 Subaru Ascent
    There are two different 7-way trailer wiring harnesses for a 2019 Subaru Ascent dependent on whether or not you have the factory tow package. If you do have the factory tow package then you should be using the Tekonsha OEM Replacement Vehicle Wiring Harness part # 118290, not the Universal Installation Kit for Trailer Brake Controller part # ETBC7. If you found a plug under the dash for the Tekonsha Plug-In Wiring Adapter for Electric Brake Controllers part # 3062-P then you have the factory...
    view full answer...
  • Does Draw Tite Trailer Hitch for 2019 Subaru Ascent Have Capacity for Towing
    I certainly understand the concerns you mentioned for the Draw Tite hitch # 76253 which fits your 2019 Subaru Ascent but Draw Tite rigorously tested the capacity of this hitch and found it has a towing capacity of 5,000 lbs and a tongue weight capacity of 750 lbs. Draw Tite is normally very conservative with their capacity figures as well and tends to err on the side of caution always in this regard. As long as you plan to tow under the capacity of this hitch and your vehicle you will be...
    view full answer...

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Info for this part was:

Edited by:
Lindsey S
Installed by:
Kathleen M
Video Edited:
Chris R
Written by:
Ronnie R
Updated by:
Isabelle B

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