As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CONDITION AIR TEMP SELECTOR ON OVERHEAD PANEL IS NOT WORKING. ACFT GROUNDED. FOUND AIR TEMP SELECTOR ASSY MOUNTING HARDWARE WASHER/NUT VERY LOOSE CAUSING AIR TEMP SELECTOR ASSY TO ROTATE WHEN KNOB TURNED. TIGHTENED MOUNTING HARDWARE, AIR TEMP SELECTOR PROPERLY ROTATES TO EACH AIR TEMP POSITION AND INDICATES PROPERLY AT EACH AIR TEMP POSITION REF 21-61-00.