As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON CLIMB-OUT FOR A RETURN FLIGHT, ENG FIRE WARNING LIGHT ILLUMINATED. DID MEMORY ITEMS, CONTACTED ATC AND STARTED TURN AND DECENT BACK TO DEPARTURE. LANDED BACK AT DEPARTURE WITH NO INCIDENT. ON THE TAXIWAY THE ENGINE FIRE WARNING LIGHT WENT OUT. WORK PERFORMED BY MECHANIC TROUBLESHOOTING SYS, BY VISUALLY INSP OF SYS, NO DEFECTS ON FIRE WIRE ALSO VISUALLY INSPECTED WIRES FOR CONNECTOR PLUG TO FIRE WALL, CONNECTOR NO DEFECTS NOTED PERFORMED FIRE WARNING ELECTRICAL TEST, OPS CK GOOD. ALSO, PERFORMED ENGINE RUN AND COULD NOT DUPLICATE PROBLEM. OPS CK GOOD IAW CURRENT PC-12/45 AMM CHAP 12-A-26-10-00-00A-040A-A.