As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFT CABIN TRIM VLV INOP LIGHT ON. CREW TURN SWITCH TO OFF POSITION. COMPLIED WITH MEL PER PROCEDURE 1. BITE CABIN TEMP CONTROLLER FAILED AFT TRIM VALVE, RESETTED 2 TIMES AND FAILED VALVE BOTH TIMES. NEED NEW TRIM VALVE. REPLACED AFT TRIM VALVE.