As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WE HAVE FOUND THAT THE STALL WARNING SYSTEM ON THIS TYPE OF AIRCRAFT IS PRONE TO FREEZE UP. MOISTURE IS INTRODUCED TO THE SYSTEM THROUGH THE SENSORY HOLE IN THE LEFT WING. MOISTURE TRAVELS TO THE LOW POINT IN THE SYSTEM LOCATED IN THE AIRCRAFT BELLY AD FREEZES UP CAUSING THE STALL WARNING SYSTEM TO NOT FUNCTION.