ON THE EVENING OF AUGUST THE 18TH I WENT TO A CONVENIENCE STORE APPROXIMATELY 1 MILE FROM MY HOME. I DID SMELL AN ODOR OF SOMETHING BURNING WHEN I EXITED THE TRUCK BUT IT DISSIPATED QUICKLY. I WENT INTO THE STORE TO PURCHASE MILK AND WHEN I RETURNED TO MY TRUCK THE ENTIRE CAB WAS FILLED WITH SMOKE AND A STRONG ODOR OF SOMETHING BURNING. THE KEYS WERE NOT IN THE IGNITION AT THE TIME. I LOOKED THROUGH THE CAB BUT COULD NOT LOCATE THE SOURCE. I OPENED THE HOOD OF MY TRUCK AND THERE WERE NO SIGNS WHAT SO EVER OF SMOKE OR FIRE. I WENT BACK TO THE CAB AND INSPECTED THE BACK SEAT AREA OF THE TRUCK. (QUAD CAB) I NOTICED A FAINT ORANGE GLOW AGAINST THE LOWER BODY OF THE TRUCK. I STARTED TO INSPECT THE LEFT REAR DOOR PANEL AND FELT THE HEAT. WHEN I GRABBED THE LOWER SECTION OF THE INTERIOR PANEL MELTING AND ON FIRE PLASTIC STARTED TO DRIP. I RAN INTO THE STORE AND GRABBED A FIRE EXTINGUISHER AND PUT THE FIRE OUT. ANOTHER CUSTOMER AT THE STORE DISCONNECTED THE BATTERY. THE TRUCK WAS TRANSPORTED TO THE LOCAL DODGE DEALERSHIP FOR REPAIRS. ALTHOUGH THE BODY SHOP STATED THE THE SOURCE OF THE FIRE MAY NOT BE ABLE TO BE DETERMINED THE TECHNICIAN WORKING ON MY TRUCK STATED THE SOURCE WAS AN ELECTRICAL SHORT WITH THE POWER WINDOW SWITCH. THE DOOR AND CARPET WILL BE REPLACED AS WELL AS ANY OTHER PARTS DAMAGED BY THE FIRE. I WILL HAVE TO PAY THE $500 COMPREHENSIVE DEDUCTIBLE. THE PANEL FOR FOR THAT DOOR HAS NEVER BEEN REMOVED OR TAMPERED WITH IN ANY WAY, SHAPE, OR FORM.