HVAC SYSTEM BECAME OPERATIONAL WITH THE IGNITION TURNED OFF FOR AN UNKNOWN PERIOD OF TIME WHILE THE TRUCK WAS PARKED IN THE GARAGE. RELAY RESISTOR MODULE OVERHEATED CAUSING MELTING OF THE RESISTOR AND CIRCUIT BOARD. TRUCK CABIN AND VICINITY AROUND THE TRUCK HAD A STRONG SMELL OF BURNING PLASTIC. TRUCK CABIN FILLED WITH SMOKE. WAS ONLY ABLE TO TURN OFF THE HVAC SYSTEM AND STOP THE BURNING BY DISCONNECTING THE WIRING HARNESS. DEALER HAD TO REPLACE THE BLOWER MOTOR, RESISTOR, MODULE CONNECTOR AND RELAY. BURNING COULD HAVE CAUSED THE ENTIRE VEHICLE TO CATCH FIRE CAUSING SIGNIFICANT DAMAGE TO OTHER VEHICLES PARKED NEARBY AND THE HOUSE IN WHICH THE GARAGE WAS ATTACHED. ISSUE WAS IDENTICAL TO SCENARIO DESCRIBED IN TRANSPORT CANADA RECALL #2011074. *TR