As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CANNOT CONTROL CABIN TEMP ON CLIMB WITH BOTH FWD & AFT CONTROLS IN FULL HOT, SUPPLY DUCT SHOWED 14 + 17C RESPECTIVELY. CABIN VERY COLD. TROUBLESHOT CONTROL CABIN TEMP SYSTEM IAW MM 21-61-00 AND FOUND TRIM AIR MODULATING VALVE AT FAULT. REMOVED AND REPLACED CONT CABIN TRIM AIR MODULATING VALVE IAW MM 21-61-95, OPS CHECKED NORMAL.