I PARKED MY TRUCK IN A BANK PARKING LOT AFTER RUNNING ERRANDS. I WENT INTO THE BANK LOBBY, LOOKED BACK, AND NOTICED MY HEADLIGHTS FLASHING. I RETURNED TO THE TRUCK, THINKING I SET OFF MY PANIC ALARM, ONLY TO FIND SMOKE FILLING THE CABIN. AFTER THE SMOKE CLEARED, I TURNED THE IGNITION KEY TO AUX POWER AND NONE OF MY ELECTRICAL SYSTEMS WERE WORKING (E.G. WINDOWS, DOOR LOCKS, ONSTAR, RADIO). AFTER INSPECTION, THE CHEVY DEALERSHIP FOUND THE MAIN BODY WIRE HARNESS HAD MELTED THROUGH FROM HEAT. THE FINAL ANALYSIS IS THAT THERE IS A SHORT IN THE WIRE HARNESS THAT CAUSED THE ENTIRE HARNESS TO MELT. DAMAGE WAS LIMITED TO THE HARNESS AND CARPET BECAUSE THE SHORT IMMEDIATELY DRAINED THE BATTERY AND DID NOT ALLOW THE HARNESS TO HEAT UP TO A COMBUSTIBLE TEMPERATURE. *TR