As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UNABLE TO HEAT PASSENGER CABIN TO PASSENGER COMFORT RANGE. TROUBLESHOT AND FOUND NO HEAT LEAVING TRIM AIR PRSOV. VERIFIED PRSOV NOT OPENING AND GOOD POWER AND GROUND. REQUIRES REPLACEMENT. REMOVED AND REPLACED TRIM AIR PRSOV PER MM 21 62 01. GROUND VERIFICATION SUCCESSFUL. SYSTEM OPS NML PER MM 21 62 01.