What was found
NR 1 ENGINE, LOOP B OVERHEAT, HANDLE LIGHTS DO NOT ILLUMINATE ON OVERHEAT TEST. ACFT GROUNDED. MOVED THE NR 1 ENGINE OVERHEAT DETECTOR SWITCH TO NORMAL POSITION. PERFORMED ALT DEACTIVATION PROCEDURES IAW CHAP 5, TABLE 3. TERMINATED LOOSE TERMINALS ON THE NR 1 ENGINE CORE FIRE DETECTION HARNESS IAW AMM 26-11-02. MEASURED OPEN CIRCUIT ON NR 1 ENGINE LEFT CORE FIRE DETECTOR ASSEMBLY. REMOVED AND REPLACED NR 1 ENGINE LEFT CORE FIRE DETECTOR ASSEMBLY. OPS TESTED GOOD IAW AMM 26-11-01.