2002 Chevrolet Avalanche 1500 Q&A
2002 Chevrolet Avalanche 1500 Question: I'm having trouble with the heater. It blows cool air.
Check to make sure that your coolant level is full and your engine reaches full operating temperature. How old is the thermostat? It probably needs replacing. - Herb Ackside
The 'mode control motor is responsible for defrost, vent and floorselections. The 'blend door' actuator , or control motor is for temperature , along with a heater control valve. Maybe check those, along with coolant and proper engine temp. - ziptie12