Temperature Valve and Heater Core

Temperature Valve and Heater Core


The temperature valve regulates the amount of total airflow that passes through the heater core. The relative amounts of warm and cool air coming from the heater core determine the temperature of the air coming from the heater duct and the defroster nozzle.

Placing the temperature knob in the BLUE (cold) zone positions the temperature valve to stop all airflow through the heater core. With the valve in this position, only unheated air is sent to the heater duct and defroster nozzle.

Placing the temperature knob in the RED (hot) zone positions the temperature valve to divert all airflow through the heater core for maximum heating.

Hot coolant from the engine is directed through the heater core and returned to the cooling system when the engine is running. The heater core transfers heat from the coolant to the air passing through the core fins.