As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FWD PACK CONTROLLER WAS INOPERATIVE, DUCT TEMP WAS STUCK ON 14, WOULD NOT MOVE REGARDLESS OF TEMP CONTROLLER POSITION. ACFT GROUNDED. PERFORMED PACK TEMP CONTROL BITE IAW FIM 21-62-801. TRIM VALVE ZONE FAULT ON NR 2 CONTROLLER. DURING TROUBLESHOOTING FOUND TRIM AIR PRSOV FAILED IN CLOSED POSITION. REMOVED AND REPLACED FWD CABIN TRIM VALVE.