As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEAR JET WIRING MANUAL 21-42-00, PAGE 7, AUXILIARY CABIN HEAT SYSTEM. WIRE NR HC47A10T, A 10-GAUGE WIRE, IS BUTT-SPLICED TO A 16-GAUGE WIRE AT THE AUXILIARY HEAT RELAY PANEL. THE BUTT-SPLICE AND THE 16-GAUGE WIRE OVERHEATED CAUSING THE PLASTIC TO MELT ON THE SPLICE AND MAKES THE 16-GAUGE WIRE BROWN. THIS IS THE SECOND OCCURRENCE OF OVERHEATING AT THIS SPLICE.