As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
STRONG ODOR OF BURNING PLASTIC DURING FLIGHT. INSPECTED LT & RT AVIONICS CABINETS, CO-PILOT, CENTER & PILOT CIRCUIT BREAKER PANEL WIRING, LT CONTROL TUBE/WIRING HARNESS COMPARTMENT. GROUND RAN ACFT WITH HEATERS & AIR CONDITIONING SYSTEMS ON AND OFF. COULD NOT DUPLICATE ODOR. ACFT RETURNED TO SERVICE.