What was found
WHILE CLIMBING TO FLT LEVEL 320, THE NR 4 ENG FIRE WARNING CAME ON, BOTH LOOP WERE INDICATING 8.5 ON THE GRAVINER SCALE, ALL OTHER PARAMETERS WERE NORMAL. ACCOMPLISHED ENG FIRE PROCEDURE AS PER QRH AND NR 4 ENG WAS SHUTDOWN. SINCE THE FIRE WARNING LIGHT ON NR 4 FIRE HANDLE WENT OUT WHEN THROTTLE WAS CLOSED IT WAS NOT NECESSARY TO DISCHARGED THE FIRE BOTTLE. REMOVED AND REPLACED PRV IAW MM 36-11-03. REMOVED AND REPLACED HSV IAW MM 36-11-60. REMOVED AND REPLACED PRV IAW 36-11-19. REMOVED AND REPLACED A&B FIRE WARNING HARNESS PER MM 26-11-00, OPS CK OK. PERFORMED NR 4 ENG RUN-UP IAW MM 71-00-00 OPS, LEAK AND INDICATIONS TEST NORMAL.