What was found
DURING CLIMB OUT FROM DCA, THE CREW RECEIVED A MAIN CABIN DOOR OPEN INDICATION ON THE RED WARNING PANEL. THE CREW FOLLOWED THE QUICK REFERENCE HANDBOOK AND LANDED AT THE NEAREST SUITABLE AIRPORT, DCA. MAINTENANCE PRESSURIZED THE AIRCRAFT AND THE MESSAGE FLICKED REPEATEDLY DURING THE INSPECTION. THE AIRCRAFT WAS THEN FERRIED TO DAY. MAINTENANCE AT DAY INSPECTED AND REPLACED THE PASSENGER DOOR LINK ROD IN ACCORDANCE WITH DORNIER SI 328-52-077. OPERATIONAL CHECKS WERE PERFORMED AND THE AIRCRAFT WAS RELEASED FOR SERVICE.