TRUCK WAS PARKED IN THE PARKING LOT OF MY PLACE OF BUSINESS FOR ABOUT 2 HOURS, THEN CAUGHT ON FIRE. IT APPEARED THAT THE FIRE STARTED IN THE FUSE BOX UNDER THE HOOD. IT MELTED EVERYTHING ON THE LEFT SIDE OF THE ENGINE. THE PLASTIC BRAKE FLUID RESERVOIR MELTED ADDING BRAKE FLUID TO THE FIRE. THE SHORT CAUSED THE BATTERY TO GET SO HOT THAT THE PLASTIC CASING MELTED. THERE WAS NO INDICATION OF A PROBLEM WHILE DRIVING THE VEHICLE TO WORK.