What was found
DURING DESCENT, CONTROL CABIN TEMPERATURE REMAINED HIGH, ABOUT 50C, DESPITE SELECTING LOWEST POSSIBLE TEMPERATURE SETTING. ALSO, TRIED SELECTING MANUAL WITH THE SAME RESULT. ACFT GROUNDED. PERFORMED PACK ZONE TEMP CONT BITE ON BOTH LT AND RT PACK ZONE TEMP CONT NO FAULTS NOTED EITHER CONTROL REF AMM 21-61-00-700-806-002. PERFORMED CABIN TEMP CONTROL AND IND OPS TEST REF AMM 21-61-00-700-807-002 MANUAL AND AUTO CONT CABIN TEMP HARD TO CONTROL. LT PACK TCV IS VERY LOUD. REPLACED LT TEMP CONTROL VALVE REF AMM 21-51-10. CABIN TEMP CONTROL & CONTROL CABIN, OPS CK GOOD REF AMM 21-61-00-700-807-002. GROUND OPS SIGNIFICANT SYS VERIFIED.