As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
OPERATOR NOTED LOW HEAT OUTPUT. MAINTENANCE REMOVED AUXILIARY ELECTRIC HEATER AND FOUND TWO OUT OF THREE HEATER COILS BURNED THROUGH WHERE THEY ATTACH TO THE WIRE HARNESS POST. ALSO NOTED SOME CARBON BUILD-UP ON ATTACH POST SCREW THREADS. CAUSE OF FAILED COILS UNDETERMINED. MAINTENANCE INSTALLED NEW AUXILIARY ELECTRIC HEATER.