What was found
(CAN) WHEN STARTING THE AIRCRAFT, SMOKE NOTED IN THE CABIN. AIRCRAFT SHUTDOWN. INSPECTION FOUND A BURNT WIRE FROM THE THRESHOLD LIGHT FUSE TO SWITCH; AND TO BAGGAGE COMPARTMENT LIGHT SWITCH TO AFT DOME LIGHT. AFT DOME LIGHT SOCKET WAS BROKEN, POSSIBLY FROM LOADING BAGGAGE. THE POSITIVE POST WAS OFF AND GROUNDED. HOWEVER, THE FUSE DID NOT BLOW RIGHT AWAY CAUSING THE WIRE TO MELT. FUSE TO BE SENT TO MANUFACTURER FOR ANALYSIS.