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Tekonsha
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2021 - 2024 Lexus ES250
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2022 - 2024 Lexus ES300h
Confirmed to Fit
2019 - 2024 Lexus ES350
Confirmed to Fit
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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: | 118878 |
| WARRANTY: | LIMITED 1 YEAR WARRANTY |
| WEIGHT: | 1.5 LBS |
| UNIVERSAL OR SPECIFIC FIT: | SPECIFIC |
| CIRCUIT PROTECTED: | YES |
| HARNESS TYPE: | MALE FEMALE |
| TERMINAL QUANTITY: | 4 |
| WIRE COLORS: | BROWN, GREEN, WHITE, YELLOW |
| WIRE QUANTITY: | 4 |
| WIRE GAUGE: | 16 GA. |
| POWER LEAD REQUIRED: | YES |
| 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.
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3 compatible vehicles
| Year | Make & Model | Notes |
|---|---|---|
| 2021 - 2024 | Lexus ES250 | Tow Harness T: Connector Assembly Drilling Required Install Time is 60 minutes |
| 2022 - 2024 | Lexus ES300h | Tow Harness T: Connector Assembly Drilling Required Install Time is 60 minutes |
| 2019 - 2024 | Lexus ES350 | Tow Harness T: Connector Assembly Drilling Required Install Time is 60 minutes |
Yes, the 2019-2022 Lexus ES350, 2022-2022 Lexus ES300h, 2021-2022 Lexus ES250 Tekonsha Plug & Play T-Connector Adapter Trailer Wiring 118878 (Part #TK118878) is designed to fit the 2021-2024 Lexus ES250.
The 2019-2022 Lexus ES350, 2022-2022 Lexus ES300h, 2021-2022 Lexus ES250 Tekonsha Plug & Play T-Connector Adapter Trailer Wiring 118878 (Part #TK118878) fits the following vehicles: 2021-2024 Lexus ES250; 2022-2024 Lexus ES300h; 2019-2024 Lexus ES350. Always verify your specific year, make, and model before ordering.
The 2019-2022 Lexus ES350, 2022-2022 Lexus ES300h, 2021-2022 Lexus ES250 Tekonsha Plug & Play T-Connector Adapter Trailer Wiring 118878 (Part #TK118878) fits 2021-2024 Lexus ES250 models. The 2024 model year is the last year covered by this part number. For newer models, check for an updated version.
The 2019-2022 Lexus ES350, 2022-2022 Lexus ES300h, 2021-2022 Lexus ES250 Tekonsha Plug & Play T-Connector Adapter Trailer Wiring 118878 (Part #TK118878) Drilling is required for installation. Basic hand tools are typically all you need.
The T-One® Connector is a vehicle towing connector that integrates with your vehicle's taillight wiring harness to enable trailer lighting. It uses a T-connector design that taps into the driver and passenger side taillight wiring, with a black box control module mounted on the driver's side. The system includes a 4-flat connector for trailer use and requires a 15 amp fuse for operation.
The manual shows installation on a Lexus ES as an example, but does not provide a complete vehicle compatibility list. Contact the manufacturer or your retailer to confirm fitment for your specific vehicle make, model, and year before purchasing.
Required tools are: trim panel remover, 10 mm socket or wrench, drill with 3/32" drill bit, wire crimpers, wire cutters, Phillips head screwdriver, and test probe. You will also need safety glasses.
The kit includes: two T-connector ends (one with yellow wire for driver side, one with green wire for passenger side), a black box control module, double-sided tape, cable ties, a white ground wire with eyelet and screw, a yellow fuse holder with 15 amp fuse, a black 12 gauge power wire, and two yellow butt connectors. A 4-flat connector is also included for storage in the rear cargo area when not in use.
Yes. Step 8 requires you to disconnect the vehicle's negative (−) battery cable before connecting the power wiring. After all wiring is complete, you reconnect the negative battery cable in step 11 and install the 15 amp fuse.
You must partially remove the plastic threshold cover, side panels, and cargo trays from the rear cargo area to expose the vehicle's taillight wiring harness. The manual also requires routing the green wire connector behind the passenger side felt panel. Reinstall all trim panels and coverings after installation, being careful not to pinch or cut wires.
On the driver's side, locate the vehicle's taillight wiring harness connector and separate it carefully without breaking the locking tabs. Insert the T-One® T-Connector end with the yellow wire between the vehicle wiring connectors and lock it into place. Repeat on the passenger's side with the green wire connector. Ensure all connector surfaces are clean and free of dirt, and verify that connectors are fully inserted with locking tabs in place.
Mount the black box on the driver's side of the vehicle using the double-sided tape provided. Secure the remainder of the harness with the cable ties provided, avoiding any areas that could cut or pinch the wire.
Drilling may be required for the ground connection. Step 5 states: locate a suitable grounding point near the black box such as an existing ground stud, or drill a 3/32" hole to secure the white ground wire using the eyelet and screw provided. Do not drill into the vehicle floor or bed. Before drilling, verify what is behind any surface to avoid damage to the vehicle or personal injury, and do not drill into any exposed surfaces.
Use a 3/32" drill bit to create the ground hole if an existing ground stud is not available.
Step 8 requires: disconnect the vehicle's negative (−) battery cable. Remove the fuse from the yellow fuse holder provided. Cut the fuse holder wire, attach the ring terminal to the vehicle's positive (+) battery cable, and connect the other end of the fuse holder to the black 12 gauge wire using the yellow butt connector provided. Route the black 12 gauge wire from the front of the vehicle rearward along the frame rail, avoiding hot pipes, heat shields, fuel tank, and any points that may pinch or break the wire. Connect the other end to the black power wire on the T-One® black box using the yellow butt connector. Finally, reconnect the negative battery cable and install the 15 amp fuse into the fuse holder.
The system uses a 15 amp fuse, installed in the yellow fuse holder provided with the kit.
Yellow wire: inserted into the driver's side taillight connector. Green wire: inserted into the passenger's side taillight connector. White wire: ground connection to a suitable grounding point near the black box. Black 12 gauge wire: power connection from the vehicle's positive battery terminal to the black box control module.
Beginning from the front of the vehicle, route the black 12 gauge wire rearward along the frame rail. Avoid hot pipes, heat shields, the fuel tank, and any other points that may pinch or break the wire. If routing the wire through a grommet and along the exterior of the vehicle, exercise the same caution to avoid hot pipes, heat shields, fuel tank, and pinch points.
Route the connector containing the green wire across the threshold and behind the passenger's side felt panel to the taillight pocket, where it connects to the passenger side taillight wiring harness.
Always wear safety glasses during installation. Before drilling, verify what is behind any surface to avoid damage to the vehicle or personal injury. Do not drill into the vehicle floor, bed, or any exposed surfaces. When routing wires, avoid hot pipes, heat shields, and the fuel tank. Do not pinch or cut wires when reinstalling trim panels. Read and follow all warnings and cautions printed on the tow vehicle's battery. Do not exceed the product's stated amperage ratings, as overloading circuits can cause fires.
After installation is complete, test and verify the installation with a test light or trailer. For the initial test, reset the vehicle electrical system by temporarily removing the key from the ignition. All connections must be complete for the T-One® Connector to function properly.
Store the 4-flat connector in the rear cargo area when not in use. When the 4-flat connector is in use, be careful not to pinch the harness in the door latch.
Do not exceed the lower of the towing manufacturer's rating (including in your vehicle owner's manual) or the specific amperage ratings stated on the product. The manual does not list the product's specific amperage rating; refer to the product label or contact the manufacturer for this specification.
The manual shows installation on a Lexus ES but does not provide a complete compatibility list. Confirm fitment for your specific vehicle make, model, and year with the manufacturer or retailer before purchasing.
Yes, disconnect the negative battery cable before connecting the power wiring in step 8. Reconnect it after all wiring is complete in step 11.
The system uses a 15 amp fuse, installed in the yellow fuse holder provided with the kit.
Matt
The staff was able to quickly assist me with locating the correct product I needed. Shipping was really fast. Item arrived in 2 days. Will be using TowUniverse again!!
May 22, 2023
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