What was found
PHL - FLT 1888 - EN ROUTE FROM MBJ TO PHL, THE NR 1 ENGINE FIRE WARNING DETECTION FAULT LIGHT ON THE ENGINE/APU FIRE PANEL ILLUMINATED. THE NR 1 ENGINE FIRE HANDLE FLASHED ON AND OFF DURING FIRE/OVERHEAT TEST WITH FAULT LIGHT ON. UPON LANDING IN PHL, LIGHT EXTINGUISHED. MAINTENANCE FOUND THE NR 1 ENGINE A/B LOOP WIRING IN CORE SECTION CHAFED AND SHORTED AGAINST PRSOV DISCONNECT BRACKET. REMOVED AND REPLACED NR 1 ENGINE CORE HARNESS. ALSO, REPLACED CORE HARNESS CONNECTOR D3088 (P/N BCREF115091) FOR CONDITION. FIRE WARNING OPERATIONAL CHECK NORMAL. (M)