As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CONTROL CABIN ZONE TEMP LIGHT ILLUMINATED. FOLLOWED QRH, LIGHT STAYED ILLUMINATED. ACFT GROUNDED. PERFORMED A PACK ZONE TEMP CONTROL BITE ON BOTH THE NR 1 AND 2 IAW FIM 21-62 TASK 801. FOUND FLIGHT DECK TRIM VALVE FAULT ON BITE, HISTORY, AND VERIFY ON THE NR 2 CONTROLLER. REMOVED AND REPLACED THE FLIGHT DECK TRIM VALVE V143 IAW AMM 21-61-21. OPS CHECKED GOOD. PERFORMED PACK ZONE TEMP CONTROL BITE ON BOTH NR 1 AND 2 IAW FIM 21-62 TASK 801. NO FAULTS.