As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AIRCRAFT DEPRESSURIZED IN FLIGHT, RETURNED TO BASE. 85 PERCENT SWITCH TERMINAL FOUND LOOSE, SHORT CIRCUITED CAUSING PRESSURIZATION SYSTEM TO SENSE ON GROUND CONDITION OPENING OUTFLOW VALVE. S149 SWITCH REPLACED AND SYSTEM FUNCTION TESTED.