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Troubleshooting Install of Redarc Tow Pro Elite That Doesn't Activate with Brake Pedal  

Updated 07/06/2026 | Published 07/03/2026

Question:

New Redarc brake controller install - 2026 Toyota 4Runner TRD Off Road Premium with tow package no integrated brake controller not functioning but steady blue light Order number 124703815 I have read the Redarc manual and tow section in 4Runner manual and I am stuck. 4Runner recognizes camper trailer is there through the 7 pin connection. Camper is 2020 nuCamp T@B 320 CSS BDL-just under 2000 pounds dry. I have towed the camper previously with a 4 door Wrangler and DrawTite brake controller.. Camper has electric brakes. 4Runner trailer light test works. Redarc button is steady blue when camper is connected but does not change to red when 4Runner brakes applied. Any ideas? TIA

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4Runner and Camper
4Runner and Camper
(click to enlarge)

Expert Reply:

Hey Beth, this issue is typically caused by a stoplight circuit not working on the brake controller wiring. So the red wire of the controller needs to see 12 volts when the brakes are applied and if not the controller doesn't know you are pressing the brakes and to start sending braking to the trailer brakes. Since you installed the # RED56CR which came with a custom install harness this is not usually how this manifests but it would be still worth checking to see if the red wire has 12 volts with brakes with a circuit tester like part # PTW2993.

Sometimes with issues like this it's a matter of just unplugging the connectors and plugging them back in so that they seat properly. Other times this can be an issue where the third brake light fuse of the vehicle is blown. You can check this by seeing if the third brake light comes on when pressing the brake pedal.

expert reply by:
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Jameson C
Beth S. profile picture

Beth S.

7/6/2026

Hi Jameson - Thanks for the response. My research was indicating the same - Redarc not getting the signal from the tow vehicle. My tow vehicle and camper are currently not in the same location, so I purchased a CURT 58272 7-Pin RV Blade Trailer Wiring Towing Vehicle Socket Tester. It includes brake controller testing, but I know the hook probe circuit tester is the recommended tool. Taking the 4Runner dash apart again is my last resort. :) I am hoping this is user error. I was doing the Curt socket testing alone, but when I engaged the manual override on the Redarc and turned up the brake intensity, the Redarc light did turn red. I know this doesn't prove everything is correct, but maybe it is a good sign that installation and wiring are functioning correctly? What do you think?

Jameson C. profile picture
Etrailer Expert

Jameson C.

7/6/2026

@BethS I would say the controller is wired up correctly. If you can find someone to press the brake pedal with that tester in that would be a good way to test the brake switch circuit as well.

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