As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED THE LT GEAR DOOR LIGHT AND LANDING GEAR INOP CAUTION CAME ON IN FLIGHT. THE FLIGHT ATTENDANT CONFIRMED THE LT SIDE GEAR DOORS WERE OPEN. THE CREW FOLLOWED THE CHECKLIST AND THE AIRCRAFT LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTED THE AIRCRAFT AND FOUND CODE 53 ON THE PSEU. THE PSEU WAS REPLACED AND THE OPERATIONAL CHECKS WERE GOOD. THE AIRCRAFT WAS RETURNED TO SERVICE.