What was found
IN FLIGHT, WHILE ACCOMPLISHING THE 'AFTER TAKEOFF' CHECKLIST, THE LEFT PACK LIGHT WAS ILLUMINATED. GROUNDED - YES. PER CREW LEFT PACK TEMP CLIMBED TO 53 DEGREES CELSIUS, THEN LEFT PACK TRIPPED OFF, TRIP RESET NO HELP. ACCOMPLISHED PACK TEMP CONTROL BITE ON BOTH CONTROLLERS, ZONE TEMP CONTROLLER 1 FAULTED "TEMP CONT VALVE", TEMP CONTROL VALVE NEEDS REPLACED L/T PACK, REF FIM 21-62 TASK 801. REPLACED LEFT TEMP CONTROL VALVE, OPS AND LEAK CHECK GOOD, REF AMM 21-51-10. BITE CHECK COMPLETED, NO DEFECTS NOTED, REF AMM 21-61-00.