As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT AT CRUISE ALTITUDE WITH CABIN HEAT ON, SMOKE WAS NOTICED COMING FROM THE HEATER AREA. REMOVED HEATER BLOWER PN ME-600-1000, SN 1632. INSTALLED SERVICEABLE HEATER BLOWER PN 500702-4491, SN AA6117 IAW SA4045-80, CH 21-40-0.