As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ON CLIMB OUT, THE CREW OBSERVED A FUSELAGE DOOR WARNING LIGHT. THE CREW ELECTED TO PERFORM AN AIR TURN BACK & LANDED BACK. TROUBLESHOOTING REVEALED DOOR LOCKED SENSOR AT AFT SERVICE DOOR OUT OF ADJUSTMENT. PROXIMITY SENSOR ADJUSTMENT CARRIED OUT IAW AMM & AIRCRAFT RTS. THERE WAS NO HISTORY THAT ANY WORK WAS PERFORMED IN THIS AREA PREVIOUSLY. PROXIMITY SENSORS ARE MANUFACTURED & INSTALLED ON DOORS & LANDING GEAR SYSTEMS.