Troubleshooting Redarc Tow Pro Elite Installation with Non-Functioning Running Lights

Question:

Hello, I have a 2016 Toyota 4Runner, and I have wired the Redarc Tow Pro Elite to the Toyota factory brake controller harness using the instructions in the question on this page 281269. The trailer running lights are not working with this wiring method when the vehicle headlights are on. Im also not getting a light on the Redarc dash controller switch. All other functions are working perfectly on the trailer including the brakes, brake lights, and turn signals. What should I do differently?

asked by: Spencer L

Expert Reply:

Since your Red Arc Tow Pro Elite # RED44FR trailer brake controller installation is mostly okay (and the trailer brakes themselves work) I suggest you check the main grounds on the trailer and 4Runner. Most of the time when a trailer's running lights do not work, but everything else does, the reason is a weak ground. This tends to show up with the running light circuit since running lights draw more power because they remain on continuously.

Remove the main trailer ground wire from the trailer frame, sand off that spot to remove any rust, paint or primer and then apply a thin coating of dielectric grease # 11755 before reattaching the ground ring terminal. If this does not correct the issue you can repeat the same process on the vehicle harness main ground wire.

expert reply by: Adam R