What was found
AT FL 330 NR 2 FIRE WARNING INDICATION. COMPLETED ENG FIRE CHECK LIST (SHUT DOWN ENGINE / FIRED FIRE BOTTLE) CHECKED LOOPS OK. COMPLETED ENGINE SHUTDOWN ABNORMAL PROCEDURE. DECLARED EMERGENCY AND LANDED AT CVG. REMOVED AND REPLACED NR 2 ENGINE FIRE TEST SWITCH PER DC8 WDW 26-01-01, OPS NORMAL. VISUALLY INSPECTED WIRING / LOOPS ON ENG. NO FAULTS NOTED. CONT ON LOG PAGE 178284 4M. RAN ENGINE FOR 30 MINUTES. FULL AIR AND ELECT. NO FAULTS NOTED.