Help Troubleshooting Trailer Lights Always On Connected To 2023 Toyota Highlander Tekonsha 7-Way

Question:

Hi there, I bought this for my 2023 hybrid highlander, the box says it’s part 22125. My trailer lights are always on as if I’m hitting the breaks. The shop tells me I need to buy a converter, I bought this about around May 2023, did it not come with a converter? If not, would this fix my issue, and do you sell the converter by itself?

asked by: Jon V

Expert Reply:

The Tekonsha OEM Replacement Vehicle Wiring Harness # TK57VR(22125) does have a converter. The square box on the harness is the converter which senses power for the tail lights, turn signals and brakes to send to the appropriate functions of the trailer. What it sounds like to me is the trailer running lights are some how sending power to the brake lights which are brighter. I would start by using a Test Light # PTW2993 or 7-way Tester # C66NR to ensure the correct functions on the connector are only active when in use. This will help you to determine if the issue is on the vehicle side of the Tekonsha harness or the trailer.

If the issue is on the trailer side it could be the tail lights were connected incorrectly that the brighter function activates off the trailers running lights. Or you have a short in the wiring allowing all the lights to get power when they shouldn't.

If the issue is on the vehicle side you would want to check your wiring and use the Test Light # PTW2993 to determine where the wiring may have a short that would cause the issue. If you are within in the 1-year warranty you can also contact Tekonsha to verify what all steps they will need for you to test to determine if the issue is with their harness/converter.

expert reply by: Bud M