Troubleshooting Redarc Trailer Brake Controller Issue Flashing Red on a 2019 Toyota Highlander

Updated 04/24/2023 | Published 04/22/2023

Question:

installed a RedArc brake contoller on my Highlander. Was working fine, but now flashing red intermittently more often than not. From reading here, it is likely a bad connection / poor voltage transfer. I used a multi tester on the tow vehicle 7 way and measure 2.09v to bc pin. Am I testing correctly?

asked by: Jim S

Expert Reply:

It sounds like you are having a ground issues on your trailer while using the Redarc Tow-Pro Liberty Brake Controller # RED24FR with your 2019 Toyota Highlander. The small amount of voltage you are seeing at your 7-way from the brake wire is what tells the controller you are connected to a trailer as it completes a circuit. This small amount of voltage is not enough to activate the brake magnets to slow the trailer. I recommend starting by checking the ground connections at the 7-way and the brakes. This voltage can have issues if there is corrosion built up for the ground connection.

expert reply by: Bud M