What was found
DURING CLIMB OUT MASTER WARNING FUSELAGE DOOR. WARNING EXTINGUISHED ON LANDING MFS SHOWED TYPE II / III DOOR OPEN. RETURNED TO FIELD. LANDING UNEVENTFUL. REMOVED FWD EMERGENCY EXIT TYPE II DOOR SENSOR TARGET ASSEMBLY IN REF WITH Q400 AMM 53-20-17-000-801 4.A.(C). INSTALLED SENSOR TARGET ASSY IAW Q400 AMM TASK 53-20-17-400-801 STEP 4A(2). RIGGED PROX SENSOR IAW Q400 AMM TASK 52-71-01-860-049. PRESSURIZED A/C IAW Q400 AMM TASK 21-31-00-710-801. DOOR STAYS IN RIG AND EMERGENCY EXIT TYPE II / III DOOR INDICATES NORMALLY ON DISPLAY UNIT. NO FURTHER DEFECTS NOTED. AIRCRAFT RETURNED TO SERVICE.