I WAS DRIVING IN MY NEIGHBORHOOD WITH MY GL 450 SEAT WARMER TURNED ON IN THE DRIVERS SEAT. I STARTED SMELLING SMOKE & THOUGHT IT WAS FROM OUTSIDE. I OPENED MY WINDOW, AND SMOKE STARTED SWIRLING INSIDE MY CAR AND STARTED GETTING THICKER WITHIN MINUTES. I PULLED THE CAR OVER TO THE STREET CURB, TURNED MY IGNITION OFF AND DISCOVERED A MELTED HOLE ABOUT THE SIZE OF A QUARTER BURNING & SMOKING. THE SWEATER I WAS WEARING ALSO HAD A MELTED HOLE IN IT. THE HOLE IN THE CAR IS ON THE LEFT SIDE OF THE DRIVERS SEAT. WE CONTACTED MERCEDES BENZ SERVICE HERE IN SAN DIEGO, AND WERE JUST TOLD TO BRING IT IN ON MONDAY - IT HAPPENED ON THURS. MORNING. SO WE ARE WAITING FOR MONDAY, BUT IN THE MEANTIME I AM AFRAID TO DRIVE MY CAR AND WANT TO REPORT THIS INCIDENT, DUE TO THE EXTREME SAFETY FACTOR OF THE SITUATION, BUT DON'T KNOW WHAT AGENCIES TO CONTACT. THIS COULD POTENTIALLY BEEN A MORE DANGEROUS SITUATION AS IT WAS A BURNING ELECTRICAL FIRE. THANK GOODNESS I COULD SAFELY PULL OVER AND TURN OFF THE POWER TO THE CAR. THANK YOU *TR