What was found
DURING OVERHEAT/FIRE TEST, NR 2 FIRE HANDLE DOES NOT ILLUMINATE AND ENGINE 2 OVERHEAT CAUTION LIGHT DOES NOT ILLUMINATE. ACFT GROUNDED. PERFORMED ENGINE/APU FIRE DETECTION BITE FOUND FAULT NR 2 ENGINE LOOP B UPPER FAN DETECTOR FAULT IAW-800 FIM 26-10-801. REMOVED ENGINE/APU FIRE DETECTION CONTROL MODULE M279. INSPECTED RACK CONNECTORS, NO DEFECTS NOTED. REINSTALLED M279 INOPERATIVE NORMAL IAW AMM 26-10-01. PERFORMED BITE, ALL FAULTS CLEARED. ENGINE FIRE AND OVERHEAT DETECTOR SYS OPS TEST PASSED.