What was found
FLT 404 - MCI - 15 MINS BEFORE LANDING, STARTED GETTING QUICK INTERMITTENT FLASHES ON THE NR 1 ENGINE FIRE WARNING SWITCH. STOPPED FOR 5 MINUTES, THEN STARTED AGAIN. CONTINUED TO LANDING. DECLARED EMERGENCY AND SHUT DOWN NR 1 ENGINE AFTER LANDING. PULLED FIRE SWITCH AND FIRED LEFT EXTINGUISHER BOTTLE. TROUBLSHOT PER MM 26-11-0, CHECKED CONTINUITY OF FIRELOOPS, OK. CHECK FOR RESISTANCE TO GROUND, OK. FOUND NR 1 FIRE TEST INOP. REPLACED FIRE DETECTOR UNIT PER MM 26-11-0, OPS CHECK OK. REPLACED NR 1 FIRE BOTTLE PER MM 26-21-11, PAGES 401-404. (M)