What was found
DCA/BOS - FLT 1503 - ON APPROACH TO BOS, THE NOSE GEAR WOULD NOT EXTEND. THERE WAS NO NOSE GEAR GREEN LIGHT. AT 1,000 FEET 'GEAR UNSAFE' ILLUMINATED ON THE MULTIFUNCTION DISPLAY. CREW CYCLED THE GEAR. ALL INDICATIONS NORMAL. FLIGHT LANDED AT BOS WITHOUT FURTHER INCIDENT. MAINTENANCE REPLACED NOSE GEAR GROUND/FLIGHT RELAY (K0687A) AND GROUND/FLIGHT CONTROL RELAY (K0686A). GEAR SWING PERFORMED. ALL OPERATIONS NORMAL. AIRCRAFT RETURNED TO SERVICE. 1. K0687A - MPN: M210D4N003. LOCATION: ZONE 255. 2. K0686A - MPN: TD1720-5001. LOCATION: ZONE 255. REF: OPERATOR CONTROL NR USAAF97042.