As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB MASTER WARNING ANNUNCIATOR ILLUMINATED FOLLOWED BY CABIN DOOR UNLOCKED ANNUNCIATOR. RETURNED TO DEPARTURE, LANDING WAS UNEVENTFUL. CABIN DOOR UNLOCKED ANNUNCIATOR SYSTEM WAS DEFERRED IAW MINIMUM EQUIPMENT LIST. ACFT WAS RETURNED TO SERVICE.