As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED. UNABLE TO CONTROL COCKPIT TEMPERATURE, SUPPLY DUCT TEMPERATURE STAYED AT 160F WITH CONTROL OFF. FLIGHT RETURNED TO FIELD, NO EMERGENCY DECLARED. REPLACED LT TEMPERATURE CONTROL VALVE, IAW AMM 21-51-10. OPERATIONS CHECK GOOD.