BLOWER MOTOR SWITCH RESISTORS, DEFECTIVE FROM FACTORY. RESISTORS GET SO HOT THEY MELT AND MELT THE END OFF THE FACTORY WIRING HARNESS. THE WIRES AND BLOWER MOTOR ARE SUPPOSE TO BE PROTECTED BY A FUSE BUT THE FUSE NEVER BLOWS. REPLACED RESISTORS IN 2013 BUT IT DID NOT LAST 1 YEAR AND BURNED UP AGAIN IN 2014! GM HAS KNOWN ABOUT THIS PROBLEM FOR MANY YEARS BUT DOES NOT CARE IF THE WIRES OVER HEAT AND CAUSE A FIRE. *TR