What was found
WHEN TESTING THE FIRE SYSTEM AND THE TEST SWITCH IS MOVED TO OVHT/ FIRE, THE FAULT LIGHT ILLUMINATES. ACFT GROUNDED. ISOLATED FAULT TO NR 1 ENG A LOOP INOPERATIVE. B LOOP OK. ACCOMPLISHED ENGINE AND APU FIRE DETECTION CONTROL MODULE BITE IAW AMM 26-10 TASK 801. FOUND FAULT A LOOP-LOW DET RESISTANCE AND ACCOMPLISHED FIM 26-10 TASK 805. RESISTANCE READINGS ARE NORMAL. FOUR CIRCUIT BREAKERS OPENED AND CLOSED. FOUND NO 28 VDC FROM PIN 5 D1002 ON CONTROL MODULE (M279) TO P8 MODULE ASSY IAW WDM 26-11-11. REMOVED AND REPLACED ENGINE AND APU FIRE CONTROL PANEL IAW AMM 26-00-01. OPS TEST PASSED AND NO FAULTS PER SAME. GROUND VERIFICATION OPERATIONAL TEST NORMAL.