What was found
DISCREPANCY: ENGINE NR 1 STRUT OVERHEAT LIGHT ILLUMINATED WHEN NR 1 THROTTLE WAS RETARDED, LIGHT WENT OUT. FINISHED CHECK LIST RESULTING IN RIGHT PACK AND NR 3 BLEED ONLY USABLE. CORRECTIVE ACTION: RAN ENGINE NR 1 AT IDLE POWER, CHECKED PYLON AREA FOR ANY LEAKS, NONE FOUND. VISUALLY CHECKED TEMPERATURE SENSOR ALL SEEMS OK. REINSTALLED PROPERLY. REPLACED FIRE OVERHEAT DETECTOR ACCESSORY UNIT FOR PRECAUTION/TROUBLESHOOTING. TESTED OK FOR SERVICE PER MM 26-14-0. INSTALLED STUB WING PANEL.