As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HEATER FAILED IN FLIGHT. ACFT DIVERTED, DUE TO ODOR OF ELECTRICAL BURNING AND SMALL AMOUNT OF SMOKE IN THE COCKPIT AREA. MX FOUND THE CYCLING SWITCH POINTS ON THE HEATER WERE ARCHING. R & R THE HEATER AND CYCLING POINTS TO CLEAR DISCREPANCY.