As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UNABLE TO ADJUST FWD OR AFT CABIN TEMP USING CONTROL KNOBS. CONT CABIN WORKS NORMAL. POSTIONED TRIM AIR SWITCH TO OFF POSITION ABLE TO CONTROL CABIN TEMPS. TEMP CONTROLLER (ZONE 2): FAULTED THE TRIM AIR MOD VALVE FOR THE FWD PASS CABIN. REMOVED AND REPLACED MOD VALVE PER: M M21 61 21. TEMP CONTROLLER FAULTS CLEARED (CONFIRM FIX).