What was found
IN DESCENT THROUGH APPROX 40,000' CABIN DOOR SEAL ILLUMINATED. AUDIBLE WIND NOISE HEARD. AT APPROX 39,000' CABIN ALTITUDE WARNING ILLUMINATED, PRESSURE ALTITUDE INCREASED TO APPROX 10,500 AND HELD UNTIL 9,500' WHEN LIGHT THEN EXTINGUISHED. AT 6,000' MSL, DOOR SEAL LIGHT FLICKERED ON THEN OFF 2-3 TIMES PRIOR TO LANDING. MOISTURE FOUND IN SUPPLY AIR SYS AND INFLATABLE SEAL. SUPPLY AIR SYS AND INFLATABLE SEAL PURGED OF MOISTURE AND OPS CHECK SATISFACTORY. ACFT RETURNED TO SERVICE.