Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Brake Light Switch: Notes
The control module receives voltage on pin 30 from the brake light switch when the brake pedal is depressed.
The control module uses information on brake light switch status (ON/OFF):
- If the brake pedal is released and then re-pressed while the ABS is operative, the control module restarts from the start of the control cycle.
- Brake light ON is one of 4 criteria for the control module to activate EBD modulation.
- A pump motor test is normally performed at 6 km/h (3.7 mph). If the brake light is ON, the test is performed at 15 km/h (9.3 mph).
- If the brake pedal is depressed during TCS modulation (brake light ON), the ESP control module disengages the TCS function for braking and select braking. Other TCS control functions remain active.
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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