As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PER SEAMC PAT AND VERBAL FROM FLIGHT CREW CONTROL CABIN ZONE TEMP LIGHT ILLUMINATED AND RESET WITH MASTER CAUTION. GROUNDED - YES. PERFORMED PACK TEMPERATURE CONTROL BITE TEST PER B737-800 FIM 21-62 TASK 801. FOUND FLT DECK TRIM VALVE FAULT ON R/H PACK/ZONE TEMPERATURE CONTROLLER. TROUBLESHOT FAULT PER FIM 21-62 TASK 832. REMOVED AND REPLACED FLT DECK TRIM VALVE ASSY WITH A SERVICEABLE UNIT PER B737-800 AMM 21-61-21. OPS CHECK AND LEAK CHECK GOOD. ETOPS GROUND VERIFICATION SUCCESSFUL.