Vehicle was parked while running errands, returned to leave and it would not start. Went to trunk to check battery connection and found that the positive battery cable had burnt in two where it connects to cable that runs to the engine compartment. Carpet cover and sound deadening coating had burnt and cable fell through trunk floor on top of gas tank. Car was towed and insurance refused to replace what caused fire, only what burnt from source ie. carpet cover and floor but not wiring. BMW dealer reports they donât know what caused cable to overheat.