As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CONT CAB ZONE TEMP LIGHT ILLUMINATED UPON MASTER CAUTION RECALL. GROUNDED-YES. PERFORMED PACK/ZONE TEMPERATURE CONTROL BITE TEST, REF B737-800 AMM 21-61-00-70-806-002. VERIFIED FLIGHT DECK TRIM VALVE FAULT, PER B737-800 FIM 21-62 TASK 834. REPLACED FWD CABIN TRIM AIR VALVE, REF AMM 21-61-21-400-801. OPERATIONS & LEAK CHECK GOOD. BITE TEST GOOD, REF AMM 21-61-00-70-806-002. ETOPS SIGNIFICANT SYSTEM, GROUND VERIFICATION TEST PASSED.