Component Inspection

IG "OFF".
Disconnect the brake light switch connector.
Measure resistance between power terminal and signal terminal of the brake light switch connector.
Specification:

Resistance between terminals of the brake light switch - ∞Ω (when the plunger is pushed down), 0Ω (when the plunger isn't pushed down).

Resistance between the terminals of the brake switch - ∞Ω (when the plunger is not pushed down), 0Ω (when the plunger is pushed down).

Fig 1: Measuring Resistance Between Power Terminal And Signal Terminal Of Brake Light Switch Connector
Courtesy of HYUNDAI MOTOR CO.
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 " procedure.
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 " procedure.