Brake Lights Not Working w/ the Pedal Pressed But Working w/ the Manual Override

Updated 12/15/2025 | Published 11/03/2024

Products Featured in This Question

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

(15)

$18.80

Hook Probe Circuit Tester

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$13.33

Question:

I have a 1999 Chevy Tahoe , my brake lights don’t work with the pedal but will work if I use the break control box on drivers side , just got this truck and don’t know why it’s doing this

asked by: Tiara D

Expert Reply:

Hey Tiara! It sounds like the problem with your 1999 Chevy Tahoe is a bad brake controller switch. This is what sends the signals to your brakes to active the trailer lights. When you use the manual override, it bypasses the need for a brake signal on the vehicle and applies power to the trailer brakes. That is why it works when you hit that button.

There's a wire that needs to attach to the stop light switch above the brake pedal. It connects to the wire on this switch that carries a signal only when the brake pedal is pressed. It should not have a signal at any other time. You will want to use a circuit tester, like item # PTW2993, to test the wires. If your brake controller red wire is not connected to the correct wire, or is loose or broken, this would cause the problem you are experiencing.

If this doesn't fix your issue you may need a new brake controller.

expert reply by: Jerred H

Jerred H.

12/15/2025

Hey Tiara, did reconnecting the brake controller wire to the stop light switch fix the issue with your Tahoe’s brake lights? Your update could make it easier for others dealing with the same wiring problem.