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.
Component Inspection
- Brake light switch Check
- Ignition "OFF" & Engine "OFF".
- Disconnect the brake light switch connector.
- Measure resistance between power terminal and signal terminal of the brake light switch A, B connector.
Specification : Resistance between terminals of the brake light switch A - ∞Ω (when the plunger is pushed down), 0Ω (when the plunger isn't pushed down).
Resistance between the terminals of the brake light switch B - ∞Ω (when the plunger is not pushed down), 0Ω (when the plunger is pushed down).
- Is the measured value within specifications?
YES
- Fault is intermittent caused by poor connection in brake light switch harness and/or HECU's connector.
Go to VERIFICATION OF VEHICLE REPAIR .
NO
- Substitute with a known-good brake light switch and check for proper operation.
If problem is corrected, replace brake light switch and then go to VERIFICATION OF VEHICLE REPAIR .
- Fault is intermittent caused by poor connection in brake light switch harness and/or HECU's connector.
NO RELATED
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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.