As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DES CHECK THE CONT CAB LIGHT OVERHEAD ILLUMINATED LIGHT. RESET WITH MASTER CAUTION RESET. QRH. NO FURTHER ACTION REQUIRED. GROUNDED - YES. PERFORMED PACK ZONE TEMP BITE PER B737-800 AMM 21-61-00-700-806-002, #2 CONTROLLER FAULT FLT DECK TRIM VALVE. REMOVED CNTRL CABIN ZONE TRIM AIR VALVE V143 PER B737-800 AMM 21-61-21-000-801. INSTALLED ZONE TRIM AIR VALVE PER AMM 21-61-400-801. PERFORMED VALVE CHECK PER SAME. OPS CHECKED GOOD. GROUND VERIFICATION TEST SUCCESSFUL.