What was found
CREW REPORTED UNABLE TO PRESSURIZE IN-FLIGHT, DUMPED FUEL AND RETURNED. CAPTAIN FOLLOWED ABNORMAL PROCEDURES AND LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE FOUND E/E COMPARTMENT DOOR PARTIALLY OPEN DOOR WAS CLOSED. THE E/E DOOR WARNING LIGHT SYSTEM WAS ALSO DEFERRED. MAINTENANCE ORDERED E/E DOOR WARNING LIGHT SWITCH. AIRCRAFT RETURNED TO SERVICE.