What was found
PACK LIGHT LIGHT ON AT CRUISE, LIGHT STAYS OFF AFTER RESET LEFT OPERATING UNDER MEL LEFT PACK SINGLE CHANNEL. COMPLIED WITH NON NORMAL. RESET WITH WARMER CONT CAB TEMP. LIGHT REMAINED OUT. 50 MINS LATER AT CRUISE LEFT PACK LIGHT AGAIN. COMPLIED NON NORMAL. LIGHT REMAINS OUT. ADD EMP:U137877 25 MINS LATER LEFT PACK LIGHT ON AGAIN. COMPLIED WITH NON NORMAL. LIGHT REMAINS OUT ADD EMP:U137877 DEBRIEFED INBOUND CREW, THEY SUSPECT LEFT PACK IS NOT COMING ON AT ALL. MADE WHINING NOISE AND OVERHEAT SMELL. PERFORMED PZTC BITE NO FAULTS. ACM IS NOT SPINNING UP AND L/H PACK OUT TEMP REACHES 95C BEFORE TRIPPING, SUSPECT ACM SEIZED, NO AIRFLOW INTO OR OUT OF LEFT PACK INLET AND EXHAUST REMOVED AND INSTALLED LEFT SIDE ACM IN REFERENCE TO AMM TASK 21-51-04-400-802-002. COMPLETED STEPS UP TO AND INCLUDING 3.I(9). CONTINUE INSTALLATION FROM INSTALLATION TEST SUBTASK 21-51-04-860-032-002 ADD EMP:399051 COMPLETED INSTALLATION IN REF TO AMM 21-51-04-400-802-002, OPS AND LK CK GOOD.