Our in-house experts typically reply within one business day.
Tekonsha
Verify Fitment
Select your vehicle to confirm this part fits.
2019 - 2025 Subaru Ascent
Confirmed to Fit
Always the correct part
We know our products
Quality Products
Free Shipping!
Always the correct part
We know our products
Quality Products
Free Shipping!
Tekonsha T-One connector (also referred to as T-Connector) wiring harnesses are the fastest and easiest way to add an electrical connector to the back of your vehicle. These connectors are used to link the wiring from your vehicle to the trailer when towing. Tekonsha T-One connectors feature custom designs to fit each vehicle make and model based on manufacturer specifications. Plus, the Plug & Play connectors on the end of the wires make it easy to install. No cutting or splicing!
Tekonsha offers the largest, most complete line of T-One connectors. To install a Tekonsha T-One wiring harness, simply locate your vehicle's wiring harness connector typically behind the vehicle taillight - unplug the connection and insert the T-Connector into the vehicle's harness. It's that easy! So what are you waiting for? Hit the road with the peace of mind only Tekonsha can provide. Life's a Journey. Stop Often.
| BRAND: | TEKONSHA |
| PART NUMBER: | 118790 |
| WARRANTY: | LIMITED 1 YEAR WARRANTY |
| WEIGHT: | 0.75 LBS |
| UNIVERSAL OR SPECIFIC FIT: | SPECIFIC |
| CIRCUIT PROTECTED: | YES |
| HARNESS TYPE: | MALE FEMALE |
| TERMINAL QUANTITY: | 4 |
| WIRE COLORS: | BROWN, GREEN, YELLOW, WHITE |
| WIRE QUANTITY: | 4 |
| WIRE GAUGE: | 16 GA. |
| POWER LEAD REQUIRED: | NO |
| ELECTRICAL SYSTEM TYPE: | 3-WIRE SYSTEM |
| HARDWARE INCLUDED: | YES |
Tekonsha is a leading manufacturer of electronic trailer brake controllers, pioneering the category in the 1970s. The lineup spans proportional units such as the Prodigy P3 and Prodigy iD, time-delayed controllers, the wireless Prodigy RF, plus vehicle-specific wiring harnesses, adapters and trailer brake components engineered for smooth, predictable stopping at any speed.
Tekonsha Engineering Company began in 1964 building RV steps and mirrors. Within a few years it had found its real calling, and by the 1970s Tekonsha was pioneering the manufacture of electronic trailer brake controllers, the product category that still defines the brand. More than half a century later it remains the reference name in trailer braking and is part of the Horizon Global group alongside Reese, Draw-Tite, Fulton, Bulldog and Wesbar.
A brake controller is the component that tells a trailer's electric brakes how hard to work and when, and getting that right is the difference between a controlled stop and a shove from behind. Tekonsha builds both major types. Proportional controllers use an internal accelerometer to sense how quickly the tow vehicle is slowing and apply trailer braking to match, so light braking stays light and hard braking is immediate. Time-delayed controllers ramp to a preset output over a fixed interval, a simpler and more economical approach that suits occasional towing.
The current brake controller range covers most of that ground. The Prodigy iD pairs with a phone through Tekonsha's EDGE technology for setup and monitoring, the P3 offers storable settings for multiple trailers and a trilingual colour LED display, the Prodigy P2 adds a dimmable display and boost mode for heavier loads, and the Voyager keeps operation simple and dependable. The Prodigy RF mounts to the trailer itself and controls wirelessly, which suits rental fleets and drivers who swap tow vehicles.
Installation is supported by vehicle-specific brake control harnesses that plug into a factory connector rather than requiring cut-and-splice wiring, along with mounting brackets and adapters. Matched controller bundles pair a unit with the correct harness. Products are tested to meet and often exceed published industry standards.
Experts available to answer your questions
Call 888-634-94941 Year
1 compatible vehicles
| Year | Make & Model | Notes |
|---|---|---|
| 2019 - 2025 | Subaru Ascent | Tow Harness T: Connector Assembly Drilling Required Install Time is 15 minutes |
The 2019-2024 Subaru Ascent Tekonsha Plug & Play T-Connector Adapter Trailer Wiring 118790 (Part #TK118790) fits 2019-2025 Subaru Ascent models. The 2025 model year is the last year covered by this part number. For newer models, check for an updated version.
Yes, the 2019-2024 Subaru Ascent Tekonsha Plug & Play T-Connector Adapter Trailer Wiring 118790 (Part #TK118790) is designed to fit the 2019-2025 Subaru Ascent.
The 2019-2024 Subaru Ascent Tekonsha Plug & Play T-Connector Adapter Trailer Wiring 118790 (Part #TK118790) fits the following vehicles: 2019-2025 Subaru Ascent. Always verify your specific year, make, and model before ordering.
The 2019-2024 Subaru Ascent Tekonsha Plug & Play T-Connector Adapter Trailer Wiring 118790 (Part #TK118790) Drilling is required for installation. Basic hand tools are typically all you need.
Yes, the T-One® T-Connector (118790-037) is designed for the Subaru Ascent. Installation involves connecting to the vehicle's 8-pin connector located behind the rear interior trim panel on the driver's side.
You will need: trim panel remover, 10mm socket and ratchet (or 10mm wrench), drill with 3/32" drill bit, 1/4" socket, Phillips head screwdriver, and a test probe. Safety glasses are also required.
Yes, you must open the vehicle's rear tailgate. On the driver's side, you will need to remove access panels, the threshold, trunk floor panels, and trays to access the 8-pin connector and ground stud.
The 8-pin connector is located behind the rear interior trim panel on the driver's side. You will insert the 8-pin tow-plug adapter into this connector and lock it into place.
Locate the existing ground stud on the driver's side behind the interior trim panel. Loosen the bolt on the stud, place the screw eyelet on the stud, and re-tighten the bolt. Ensure all other ground connections remain secure when removing and reattaching the ground stud.
Yes, a drill with a 3/32" drill bit is listed as a required tool. However, the manual does not specify the exact location or purpose of this hole.
Store the 4-flat connector in the rear cargo area when not in use.
Secure the rest of the T-Connector harness using the cable ties provided with the product. Take care to avoid areas where the cable could be cut, pinched, or melted.
Test and verify the installation using a test light or by connecting an actual trailer once installed. For the initial test, reset the vehicle's electrical system by temporarily removing the key from the ignition. All connections must be complete for the T-One® T-Connector to function properly.
Do not exceed the stated product ratings or the lower of the towing manufacturer rating (including in your vehicle owner's manual) or specific amperage ratings stated on the product. Overloading circuits can cause fires. Always wear safety glasses during installation and follow all warnings and instructions included with the product.
The manual does not explicitly state whether the battery must be disconnected before installation. However, it does instruct you to reset the vehicle's electrical system by temporarily removing the ignition key for the initial test after installation.
The T-One® T-Connector (118790-037) is designed for the Subaru Ascent.
A 3/32" drill bit is required.
Yes, you must open the rear tailgate and remove access panels, threshold, trunk floor panels, and trays on the driver's side to access the 8-pin connector and ground stud.
Do not exceed the stated product ratings or the lower of the towing manufacturer rating. Overloading circuits can cause fires. Always wear safety glasses during installation.
Use a test light or connect an actual trailer to verify installation. Reset the vehicle's electrical system by temporarily removing the ignition key for the initial test.
Free Shipping
Ships free on all orders
Authorized Dealer
Quick Ship
In stock and ready to ship — order now!
FREE ShippingFREE SHIPPING
Estimated delivery Wed, Sep 16 - Sat, Sep 19
Order before 2 PM EST Monday–Friday for same-day processing
Guaranteed safe & secure checkout
Total for 4 items:
$141.88
Jennifer
Ordered online. Shipment arrived on time and with all the correct parts. Great customer service and friendly staff. Also, pricing was great!
May 22, 2023
