Trailer Digital Wiring Harness for Tesla Model 3 (TM3-TDW03-US)
The harness provides a direct plug-in solution to wire the lights of a trailer on a Tesla Model 3 car. Installing this harness involves no modification of the car. Alternative solutions involve splicing car wires, pulling wires from the inside of the car, drilling, and installation is laborious.
The harness works on Model 3 cars that are equipped with a trailer connector (2019 and newer models). This connector is located under the rear bumper fascia (see photo).
The harness plugs directly into the Tesla connector and converts the digital signal into the standard US analog trailer signals (4-prong connector: Ground, Lights, Brake & Left Turn, Brake & Right Turn). There is no need for any other connections. The 4-prong connector includes LEDs that show the state of the signals.
The harness is a read-only device; It does not interfere with the car functionality and does not show on the car’s control screen.
The TM3-TDW03-US device is a solid-state model designed for LED equipped trailers.
Overloading circuits can cause fire. DO NOT exceed stated product ratings. Read vehicle’s owner’s manual & instruction sheet for additional information.
Do not operate the converter if defective or if the case or wires are damaged.
Install Instructions:This solid-state version of the converter (TM3-TDW03-US) is made for trailers with LED lights. The max load is 1A on each of the 3 circuits (that is max 1*12=12W LED bulbs each). Check trailer specifications before installing.
Structural Integrity: The converter in encased within a sealed box. Inspect the box for its structural integrity. DO NOT INSTALL the converter on the car if the case is broken, the cap was detached, or in any way that the case is improperly sealed. Please, contact us and describe the problem.
Do not remove the screws on the case. Do not open the case of the converter. Do not remove the USB cover.
Testing aside from the car: The converter was tested successfully before shipping. However, the converter can be easily tested by powering it with 12VDC on the 2 side tabs of the connector that is to plug into the car. These are marked + and – on the case on the connector side. The center tab is the Data, and should be left disconnected. The test is passed if in approximately 3 seconds after the power is applied the 3 LEDs on the trailer connector blink in sequence.
Testing at the time of mounting on the car: If the taillights of the car are disconnected (as they normally are when you remove the bumper to install the hitch receiver and gain access to the Tesla trailer conector), connect them back before testing. Plug the converter into the Tesla trailer connector, all the way in until connector latch is engaged. Provided that the Tesla is awake, approximately 3 seconds after the power is applied the 3 LEDs on the trailer connector blink in sequence, as in the test above.
Then, command the turn signals, lights, and brake lights. The respective function should be shown by the LED on the 4-prong connector (marked).
Finally, plug in the trailer (with LED lights) and check the functionality like above (turn signals, lights, and the brake) on the trailer lights.
The converter has built in protection for short circuits. If a circuit is shorted, the respective light is temporarily disabled. If the trailer lights are not working properly, unplug the trailer and check the functionality on the connector LED. That will help debugging the problem, observing which/if any trailer circuit is shorted or disconnected.
Note: Tesla Model 3 also includes circuit protections that may sense short or overloaded circuits. If that protection is triggered, the car will stop the 12VDC power on the trailer connector. The power should reset itself in approx. 30min (provided that the short condition was cleared).
Software updates: The converter includes a USB plug that is covered with a plug. The USB port may be used for future software updates, should an update become necessary. Do not unnecessarily uncover the USB plug as this may deteriorate the seal.
Installation Place: The case of the converter is made to be watertight. However, it is good to install it in a place that is as dry as possible.
- Option 1: The converter may be mounted (attached with plastic ties) under the bumper fascia above the bumper, where the Tesla trailer connector is located. However, this place is not accessible after you replace the fascia.
- Option 2: If you plan to have access to the adapter (and be able to remove it without removing the fascia), it is possible to pull the Tesla connector below the bumper and install the adapter below as well. However, this place is lower to the ground, so at a boat ramp for example water may accidentally reach the converter and its connections.
1-year limited warranty from the date of purchase. The product is warranted to be free of defects in materials and workmanship under normal use. No other warranties are expressed or implied except as set forth herein.
Should the device become defective under the limited warranty above, we will replace it free of charge with a similar model, provided that you contact the manufacturer over the website and return the defective item at your shipping expense. The replacement will be shipped free of charge.
The buyer assumes all responsibility for use and legal compliance, including the installation on vehicle and operation in conjunction with a trailer. Do not use this product unless and until you (the Buyer) have carefully read this Disclaimer of Liability. Be sure to abide by all local, state and federal laws, including but not limited to vehicle safety and traffic laws. It is your responsibility to know what those laws are and how they apply to you. The installation of this product on your vehicle indicates that you have (a) had the opportunity to inquire about applicable local, state and federal laws and (b) read and understand, and accept all of the terms of, this Disclaimer.