As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RED RESIDUAL PRESSURE LIGHT ILLUMINATED ON CABIN DOOR AND MCD CONTROL PANEL. CABIN PRESSURE AT ZERO.REMOVED ELECTRICAL CONNECTOR 71WN-A FROM CABIN PRESSURE DETECTION SWITCH. RECONNECTED CONNECTOR RESIDUAL PRESSURE LIGHT WENT OUT. SYSTEM OPERATES NORMAL REF A300 AMM 52-73-00.