What was found
LEFT FIRE DET SYSTEM INOP, LIGHT ON IN FLIGHT. VERIFIED SQWAWK, T/S SYSTEM BY SWAPPING LT & RT FIRE DETECT CONTROLS, NO HELP. REMOVED UPPER AND LOWER LT ENGINE COWLINGS. INSPECTED FIRE LOOP AND CHECKED RESISTANCE, FOUND WITHIN LIMITS. CHECKED SYSTEM WIRING, NO FAULTS FOUND. CLEANED ALL SYSTEM WIRING CONNECTORS AND FIRE LOOP CONNECTIONS. SYSTEM TEST GOOD IAW THE CE MM & WDM CHAP 26-10-01. RETURNED AIRCRAFT TO NORMAL.