What was found
PACK L MSG AT LEVEL OFF, AIR COND RESET SW NO HELP. AIR COND PAGE INDICATES NORMAL PACK FLOW, NORMAL PACK OUT TEMPS AFTER RESET, BUT EICAS MSG AND PACK OFF LT ON OVERHEAD REMAIN ON. REPLACED LOWER AIRCONDITIONIN PACK LOWER LEFT FLOW CONTROL VALVE. LOWER LEFT FCV WAS NOT IN COMMANDED POSITION. IT APPEARS VALVE WAS STUCK IN CLOSED POSITION. AFTER REPLACEMENT, LEFT PACK CHECKED NORMALLY. A/C OK FOR RETURN TO SERVICE.