As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FWD CABIN TEMP CONTROL FAILED TO CONTROL DESIRED TEMP. CREW COMMENTS: FWD AND MID CABINS EXTREMELY COLD. AFTER EXTENSIVE TROUBLE SHOOTING FOUND FAULTY FWD TRIM AIR VALVE AND LOW LIMIT CONTROL VALVE. REPLACED BOTH VALVES OP CHECKED GOOD. AC OK FOR SERVICE.