As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT FL 380 GOT ZONE TEMP LIGHT CONT CABIN IT RESET WHEN WE DECREASED THE CONT CABIN TEMPERATURE (1 CONTROLLER IS MEL'D). GROUNDED - YES. REF MEL 21-21G, CONFIRMED FAULT. REMOVED AND REPLACED DEFECTIVE FLIGHT DECK TCV (V143) PER AMM 21-61-21, OPS CK NML REF B737-800 AMM 21-61-00-700-806-002.