As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT, THE PILOT NOTICED THE CABIN VENT BLOWER FAN OPERATION BECAME VERY LOUD (SCREECHING) AND A STRONG BURNING ODOR WAS NOTED. THE AC/FA BLOWER CIRCUIT BREAKER BLEW SHORTLY THEREAFTER; AN UNEVENTFUL RETURN TO THE AIRPORT WAS MADE. WHEN A MAINTENANCE PERSON RESET THE BREAKER TO CONFIRM THE ISSUE, IT IMMEDIATELY WOULD BLOW. IT WAS CONFIRMED THE FAN MOTOR HAD OVERHEATED AND FAILED.