The heater system delivers warm air to the passenger compartment after the engine reaches the normal operating temperature. Outside air and the air from the passenger compartment pass through the heater core. The hot engine coolant heats this air. The heated air travels to the passenger compartment via the ducts and the outlets.

The heater control unit allows the operator to operate the heater and ventilation system. The heater control unit has 4 levers that control the following settings:

The temperature lever controls the temperature of the air delivered to the passenger compartment. This lever opens and closes the air mix door controlling the amount of air which passes through and around the heater core.

The mode lever allows the driver to select the following air outlets:

The blower speed lever controls a 4-speed blower motor and fan. The blower speed lever allows the driver to regulate the amount of air, cold or warm, delivered to the passenger compartment.

The fresh/recirc lever controls the air inlet of the blower. In recirculate mode, the blower takes the inside air, circulates the air through the heater system, and delivers the air into the passenger compartment. The recirculate mode heats the passenger compartment faster. However, during the normal heater operation, use the fresh mode in order to prevent window fogging. In the fresh mode, the blower circulates outside air through the heater system, and delivers the air into the passenger compartment.