As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING RECALL, THE AFT CABIN ZONE TEMP LIGHT ILLUMINATED. WHEN MASTER CAUTION IS PRESSED THE LIGHT GOES OUT. ACFT GROUNDED. PERFORMED LT PACK ZONE TEMP CONTROLLER BITE, IAW AMM 21-51-00. FOUND ZONE TRIM VALVE FAULT IN CURRENT HISTORY AND VERIFY. REMOVED AND REPLACED AFT ZONE TRIM VALVE IAW AMM 21-61-21. OPS AND BITE CHECKED GOOD IAW AMM 21-51-00 AND 21-61-00.