THIS VEHICLE IS FACTORY EQUIPPED WITH A DELCO/BOSE SOUND SYSTEM. I WAS DRIVING DOWN MY DRIVEWAY AT 5 MPH. AFTER APPROXIMATELY 3 MINUTES AND 1/4 MILE, THE RADIO SOUND BECAME DISTORTED AND INTERRUPTED. THE VEHICLE'S VOLTAGE DISPLAY INDICATED 13.3 VOLTS, RATHER THAN THE NORMAL 14.2 OR ABOVE. I TURNED OFF THE RADIO. I NOTICED AN ODOR I IDENTIFIED AS "HOT ELECTRICAL." I IMMEDIATELY PULLED INTO A NEIGHBOR'S DRIVEWAY AND SHUT OFF THE VEHICLE'S IGNITION KEY. VISIBLE SMOKE WAS FLOWING INTO THE PASSENGER COMPARTMENT THROUGH THE AREA OF THE LEFT REAR RADIO SPEAKER UNDER THE REAR WINDOW. I OPENED THE ENGINE COMPARTMENT HOOD TO ACCESS THE BATTERY AND OPENED THE TRUNK. THE TRUNK LINER MATERIAL ON THE ROOF OF THE TRUNK BETWEEN THE SEAT BACK AND TRUNK OPENING WAS BURNING. THE FLAMES WERE SPREADING IN A CIRCULAR PATTERN CENTERED ON THE LEFT REAR SPEAKER. I PULLED THE BURNING MATERIAL FROM THE VEHICLE AS MY FRIEND BROUGHT ME A DRY CHEMICAL FIRE EXTINGUISHER. I PUT OUT THE FIRE AS ANOTHER FRIEND DISCONNECTED THE NEGATIVE BATTERY CABLE. THESE SPEAKERS HAVE AN ELECTRONIC MODULE MOUNTED TO THEM. THE MODULE WAS BURNED AND THE WIRES LEADING TO IT WERE BURNED AS FAR BACK AS THE TRUNK LINING MATERIAL HAD BURNED. I ISOLATED THE BURNED MODULE AND DAMAGED PORTION OF THE WIRES LEADING TO IT BY CUTTING THE WIRE HARNESS. I INSULATED THE WIRES AND CONNECTED THE BATTERY. THE VEHICLE STARTED NORMALLY. THE RADIO PLAYED NORMALLY THROUGH THE REMAINING SPEAKERS. THE VOLTAGE INDICATOR SHOWED NORMAL VOLTAGE, 14.2