What was found
UPON PREFLIGHT FOUND FIRE DETECTION LOOP B INOP ON NR 2 ENGINE. DUPLICATED FAULT HARD FAIL NR 2 ENG B LOOP FIRE LOOP. M279 ENG/APU FIRE OVHT DET CONTROL MODULE BITE SHOWS OPEN CKT/BAD DETECTOR (3 RED LIGHTS). CHECKED ALL 4 DETECTORS RESISTANCES ALL CHECKED GOOD. FOUND HARNESS (MW0316) RESISTANCE BETWEEN UPPR FAN DET (M1757) & LWR FAN DET (M1758) READ 2K OHMS. FURTHER TROUBLESHOOTING FOUND BROKEN TERMINAL LUG AT UPPR FAN B LOOP DET (M1757) RE-TERMINATED LUG. NR 2 ENGINE B LOOP FIRE DET OPS CHECK NORMAL REF AMM TASK 26 11 00.