As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE AT FL180, THE CARGO DOOR WARNING LIGHT CAME ON. CREW FOLLOWED CHECKLIST AND REQUESTED LOWER ALTITUDE. THE LIGHT WENT OUT, AND CREW LANDED WITHOUT INCIDENT. THE LIGHT WAS DEFERRED PER MEL. THE SWITCH WAS FOUND AT LIMITS OF ADJUSTMENT. THE MICROSWITCH & MICROSWITCH ACTUATOR ARE SCHEDULED FOR REPLACEMENT.