As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT WAS STARTING AIRCRAFT DURING GROUND IDLE. TURNED AIR-CONDITIONING ON, CREW REPORTED SMOKE EMITTING FROM PILOT AND CO PILOTS VENTS. CREW SHUT DOWN AIRCRAFT AND ALERTED MAINTENANCE. MAINTENANCE WAS ABLE TO SEE THE RESIDUAL SMOKE, PULLED THE FAN MOTORS TO EXAMINE THE INTERNAL CONDITION OF THE EVAPORATOR. FOUND MELTED PLASTIC ON THE RESISTOR ON THE EVAPORATOR, AND THE RESISTOR ON THE OTHER EVAPORATOR LOOKED TO HAVE BURN MARKS ON IT.