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Tekonsha
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2021 - 2023 BMW X4
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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: | 118887 |
| 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: | 18 AWG, .85 AVSS |
| POWER LEAD REQUIRED: | YES |
| ELECTRICAL SYSTEM TYPE: | 2-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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1 compatible vehicles
| Year | Make & Model | Notes |
|---|---|---|
| 2021 - 2023 | BMW X4 | Tow Harness T: Connector Assembly Drilling Required Install Time is 60 minutes |
The Tekonsha T-One T-Connector Custom Harness, 4-Way Flat, w/Circuit Protected ModuLite HD Module 118887 (Part #TK118887) fits 2021-2023 BMW X4 models. The 2023 model year is the last year covered by this part number. For newer models, check for an updated version.
The Tekonsha T-One T-Connector Custom Harness, 4-Way Flat, w/Circuit Protected ModuLite HD Module 118887 (Part #TK118887) fits the following vehicles: 2021-2023 BMW X4. Always verify your specific year, make, and model before ordering.
Yes, the Tekonsha T-One T-Connector Custom Harness, 4-Way Flat, w/Circuit Protected ModuLite HD Module 118887 (Part #TK118887) is designed to fit the 2021-2023 BMW X4.
The Tekonsha T-One T-Connector Custom Harness, 4-Way Flat, w/Circuit Protected ModuLite HD Module 118887 (Part #TK118887) Drilling is required for installation. Basic hand tools are typically all you need.
The T-One® Connector is a vehicle-integrated wiring module that provides a 4-way flat connector for trailer lighting. It connects to your vehicle's taillight wiring harness and battery to supply power and ground to a trailer. The module includes a black box that mounts inside the vehicle and routes wiring to both driver and passenger side taillights, with a 4-flat connector stored in the cargo area when not in use.
The T-One® Connector (118887) is designed for the BMW X4. However, Horizon Global recommends visiting their website at www.horizonglobal.com for the most up-to-date information regarding specific application years and trim levels, as these details are not provided in this installation manual.
Required tools are: safety glasses, flat blade screwdriver, wire stripper, wire crimper, 10 mm socket, ratchet, trim panel remover, heat gun, fish wire, and a test light. The hardware kit includes perma seal butt connectors, ring terminals, #8 screws, a 15 amp fuse, double-sided tape, fuse holder, 6" wire ties, and a fuse holder. A Phillips screwdriver is also mentioned as an alternative for removing the trim panel.
Yes. You must disconnect and isolate the vehicle's negative battery cable before beginning installation. The manual specifically warns: DO NOT touch the negative battery terminal to the positive battery terminal, as serious injury and damage to the vehicle's electrical system can occur. The negative cable is reconnected after the power connections are complete (step 12 for standard installation, step 12 for cargo area installation).
The installation difficulty is rated as Intermediate. This rating is based on the time and effort involved and may vary depending on installer expertise and vehicle condition, as well as the availability of proper tools and equipment. Specific installation times are listed on Horizon Global's website or in downloadable application guides.
Drilling may be required depending on your vehicle's configuration. The manual states: 'Locate a suitable grounding point near the black box such as an existing ground stud or drill a 3/32" hole and secure the white wire using the eyelet and screw provided.' If an existing ground stud is available, drilling is not necessary. If you must drill, the hole size is 3/32". Critical warnings: DO NOT drill into the vehicle floor or bed, DO NOT drill into any exposed surfaces, and verify what is behind any surface prior to drilling to avoid damage to the vehicle and personal injury.
The T-One® Connector uses a 15 amp fuse. The fuse is installed in the yellow fuse holder provided in the hardware kit. The fuse holder is connected between the vehicle's positive battery cable and the black 12 gauge power wire of the module. After installation is complete and all connections are verified, the 15 amp fuse is inserted into the fuse holder.
The T-One® Connector uses the following wires: yellow wire (driver side taillight connector), green wire (passenger side taillight connector), black 12 gauge wire (power from vehicle battery positive terminal through fuse holder), and white wire (ground connection to vehicle chassis). The module's black box contains the black power wire that connects to the fuse holder via a yellow heat shrinkable butt connector.
The black 12 gauge power wire connects to the vehicle's positive battery terminal through a fuse holder and ring terminal. Procedure: (1) Disconnect the vehicle's negative battery cable. (2) Cut the fuse holder wire and attach the ring terminal provided. (3) Secure the ring terminal to the vehicle's positive battery cable. (4) Connect the other end of the fuse holder to the black 12 gauge wire on the module's black box using the yellow heat shrinkable butt connector provided. (5) Reconnect the negative battery cable. (6) Install the 15 amp fuse into the fuse holder. Do not connect the module power wire to a support battery on vehicles with Start/Stop option; connect only to the main vehicle battery.
Yellow heat shrinkable butt connectors are provided to splice the fuse holder wire to the module's black power wire and to connect the black 12 gauge power wire to the module. After inserting the wires into the connector, use a heat gun to shrink the tubing. Start heating in the center of the splice connector, then heat from the center outward to the edges on each end until the tubing shrinks and sealant flows. Allow the connector to cool before inspecting the splice. This procedure is critical for a watertight connection.
Route the black 12 gauge wire rearward along the frame rail from the front of the vehicle, avoiding 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, continue to avoid hot pipes, heat shields, the fuel tank, and pinch points. The wire must reach the module's black box, which is mounted inside the vehicle near the taillight area.
The manual provides two installation procedures. The first variant (steps 1-13, first section) involves accessing the taillight wiring from the rear hatch by removing the plastic threshold cover, cargo trays, and side panel on the driver's side. The second variant (steps 1-13, second section) involves accessing the taillight wiring from the cargo area by removing the cargo floor covering and rear side cargo panels. Both variants mount the black box in the cargo/taillight area and route wiring to both driver and passenger side taillights. The choice depends on your vehicle's configuration and which access point is more suitable.
The T-One® Connector has two ends with different colored wires that insert between the vehicle's taillight connectors and the taillights themselves. On the driver's side, insert the T-One® Connector end containing the yellow wire (or yellow and brown wires in cargo area variant) between the vehicle and taillight connector. On the passenger's side, insert the T-One® Connector end containing the green wire between the vehicle and taillight connector. All connector surfaces must be clean and free of dirt. Be careful not to break the locking tabs when separating and reconnecting the vehicle's original connectors.
Mount the black box using the double-sided tape provided. First, clean the flat mount surface area using a 50-50 mixture of rubbing alcohol and water. Choose a suitable mounting point in the cargo/taillight area near where the ground wire will connect. In the cargo area variant, ensure the lighting module is mounted so that the wire side of the module is pointed towards the ground to prevent water buildup. The black box should be positioned to allow the white ground wire to reach a nearby ground stud or drilled hole.
The white ground wire must be secured to the vehicle chassis. Locate a suitable grounding point near the black box, such as an existing ground stud. If no existing ground stud is available, drill a 3/32" hole and secure the white wire using the eyelet and screw provided. Before drilling, clean dirt and rustproofing from the area. Critical: DO NOT drill into the vehicle floor or bed, DO NOT drill into any exposed surfaces, and verify what is behind any surface prior to drilling. In the cargo area variant, the ground white wire is reconnected to the battery after the negative battery cable is reconnected.
Route the harness containing the green wire to the passenger side, crossing the threshold and behind the passenger's side felt panel to the taillight pocket (first variant). In the cargo area variant, route the T-One® Connector ends containing the green wire through the opening and under the metal cargo hook rails and along the threshold to the passenger side. Route the black 12 gauge wire and ground white wire under the driver's side metal cargo hook rails to the battery compartment. After installation, route the 4-flat connector through the driver's side panel and threshold into the storage compartment for storage when not in use. Be careful not to pinch or cut wires during reinstallation of trim panels.
After all connections are complete and the 15 amp fuse is installed, 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. Ensure all connections are complete and secure before testing. If the 4-way connector is not functioning, refer to the troubleshooting guide to diagnose the issue.
Key safety warnings: (1) Always wear safety glasses during installation. (2) DO NOT exceed the lower of the towing manufacturing rating (including in your vehicle owner's manual) or the specific amperage ratings stated on the product. (3) DO NOT touch the negative battery terminal to the positive battery terminal; serious injury and damage to the vehicle's electrical system can occur. (4) Overloading circuits can cause fires. (5) DO NOT connect the module power wire to a support battery on vehicles with Start/Stop option; connect only to the main vehicle battery. (6) Before drilling, verify what is behind any surface to avoid damage to the vehicle and personal injury. (7) Route the black 12 gauge wire away from hot pipes, heat shields, fuel tank, and pinch points. (8) Read and follow all warnings and instructions printed on the tow vehicle's battery.
Routine maintenance includes: (1) Clean the 4-way flat connector after each use. (2) Perform a pre-trip inspection of the 4-way flat harness to ensure no damage to terminals and connection points for proper lighting connection and operation. (3) Ensure the 4-way flat harness does not get pinched in door latches, trailer connection points, or contact the road surface. (4) Clean connections and add dielectric grease (sold separately) to the terminal pins. These steps help ensure reliable operation and prevent corrosion and damage.
The hardware kit includes: perma seal butt connectors (yellow heat shrinkable type), ring terminals, #8 screws, a 15 amp fuse, double-sided tape, a fuse holder, 6" wire ties, and a yellow fuse holder. These components are used to connect the power wire to the battery, ground the module, splice wires, and secure the module and wiring in place.
Horizon Global provides a limited 1-year warranty to the original consumer purchaser. The product is warranted to be free from material defects in both material and workmanship, provided installation and use are in accordance with product instructions. The warranty does not cover normal wear and tear, damage from abuse, neglect, misuse, accidents, misapplication, overloading, improper installation, improper maintenance, or alterations made by anyone other than Horizon Global (except alterations made pursuant to product instructions in a workmanlike manner). If the product does not comply with the warranty, Horizon Global will replace it without charge or refund the purchase price at their option. Repair or replacement is the sole remedy. To make a claim, contact Horizon Global at 1-800-632-3290 or 127 Public Square Suite 5300, Cleveland, OH 44114, and provide the model number and purchase receipt.
Contact Horizon Global technical support at: Phone: 800-632-3290, Email: TechnicalSupport@horizonglobal.com, or Website: www.horizonglobal.com. You can also scan the QR code on the manual for step-by-step photo installation instructions or to access French or Spanish language instructions by entering part number 118887.
Yes, the T-One® Connector (118887) is designed for the BMW X4. Visit www.horizonglobal.com for current application years and trim levels.
Required tools: safety glasses, flat blade screwdriver, wire stripper, wire crimper, 10 mm socket, ratchet, trim panel remover, heat gun, fish wire, and test light. The kit includes perma seal butt connectors, ring terminals, #8 screws, 15 amp fuse, double-sided tape, fuse holder, and 6" wire ties.
Yes, you must disconnect and isolate the vehicle's negative battery cable before installation. Reconnect it after all power connections are complete and the 15 amp fuse is installed.
Drilling may be required. If an existing ground stud is available, no drilling is needed. If you must drill, the hole size is 3/32". DO NOT drill into the vehicle floor, bed, or exposed surfaces. Verify what is behind any surface before drilling.
The T-One® Connector uses a 15 amp fuse installed in the yellow fuse holder provided. The fuse connects between the vehicle's positive battery terminal and the module's black power wire.
Yellow wire (driver side taillight), green wire (passenger side taillight), black 12 gauge wire (power from battery), and white wire (ground to chassis). The module's black box contains the black power wire that connects to the fuse holder.
Always wear safety glasses. DO NOT exceed towing manufacturing rating or product amperage ratings. DO NOT touch negative to positive battery terminal. DO NOT connect module power to support battery on Start/Stop vehicles; use main battery only. Overloading circuits can cause fires. Route power wire away from hot pipes, heat shields, and fuel tank. Test installation with test light or trailer after completion.
Clean the 4-way flat connector after each use. Perform pre-trip inspections to check for terminal damage and ensure the harness is not pinched. Add dielectric grease to terminal pins. Ensure the harness does not contact the road surface or get pinched in door latches.
Check the following in order: (1) Ensure the T-One® Connector ends are fully inserted and locked in place. (2) Remove the module's power fuse for 10 seconds and repeat the test. (3) Check chassis grounds and ensure ring terminals are in full contact with the vehicle chassis. (4) Verify the fuse is fully inserted into the fuse holder with no breaks. (5) Confirm the fuse holder is connected properly to the positive post of the battery. (6) Using a tester or voltmeter, check for voltage on either side of the yellow butt connector near the module. (7) If installation activated circuit protection, start the vehicle and turn all functions off (tail/headlights, brake, and turns), then remove the module power fuse for 10 seconds and repeat the test.
Check the following: (1) Ensure the fuse is fully inserted into the fuse holder and has no breaks. (2) Verify the fuse holder is connected properly to the positive post of the battery. (3) Remove the fuse for 10 seconds and repeat the test. (4) Ensure the module is connected to B+ (battery positive). (5) Using a tester or voltmeter, check for voltage on either side of the yellow butt connector near the module. (6) Remove the module power fuse for 10 seconds and repeat the test. (7) If installation activated circuit protection, start the vehicle and turn all functions off (tail/headlights, brake, and turns), then remove the module power fuse for 10 seconds and repeat the test.
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