What was found
YYZ - ON CLIMB-OUT AFTER TAKEOFF, THE ENGINE FIRE BELL AND LIGHT OPERATED INDICATING AN ENGINE FIRE. THE NR 3 ENGINE FIRE HANDLE WAS LIGHTED. THE EMERGENCY CHECK LIST WAS COMPLETED. THE AIRCRAFT RETURNED TO YYZ WITHOUT INCIDENT. NO FIRE WAS VISIBLE BY THE GROUND CREW. THE NR 3 ENGINE FIRE DETECTION ELEMENT AND FORWARD CONNECTOR WERE REMOVED AND REPLACED. ENGINE RUNS WERE PERFORMED AND ALL OPERATIONAL CHECKS WERE GOOD IAW MM 26-10-0. THE AIRCRAFT WAS RETURNED TO SERVICE. CONNECTOR PART NUMBER FRFE1253SOX. (X)