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 COMES ON AT RECALL. GOES OUT WITH MASTER CAUTION RESET. GROUNDED-YES. PERFORMED BITE CHECK, REF B737-800 AMM 21-61-00 FOUND FLIGHT DECK TRIM AIR FAULT. REMOVED AND REPLACED CONTROL COMPT TRIM AIR MODULATING VALVE, REF AMM 21-61-21. OPERATIONS CHECK NORMAL.