As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON M/C RECALL CONT CAB TEMP AND AIR COND MASTER CAUTION LTS ILLUMINATE. BOTH LTS EXTINGUISH WHEN MASTER CAUTION PANEL RESET. GROUNDED - YES. RELEASED PER MEL 21-21F FLIGHT DECK TEMP CONTROLLER SYSTEM INOO. ACCOMPLISHED PACK/ZONE TEMPERATURE CONTROLLER BITE TEST PER B737-800 AMM 21-61-00-700-806-002. #2 CONTROLLER FAULTED FLT DECK TRIM VLV FAILED. REMOVED AND REPLACED TRIM AIR MODULATING VALVE (CONTROL COMPARTMENT) LEA CHECK, NO LEAK NOTED. REF AMM 21-61-21. RE-ACCOMPLISHED PACK ZONE TEMP CONTROL BITE NO FAULTS.