The blend-air type heater system is used on all models. The blend-air method on vehicles without air condition uses a controlled flow system with the engine coolant flow controlled through the heater core, with the use of a heater coolant shut-off valve. The temperature of the heated air entering the passenger compartment is controlled by regulating, with the temperature control lever and blend door, the quantity of air which flows through the heater core air passages or fins, then blending the heated air with a controlled amount of cool fresh air which bypasses the heater core. The air flow for the heating system is through the cowl air intake and into the heating system. Defroster operation is controlled by the air control lever and cable, or vacuum servo motor, moving the defroster damper to direct heated air to the defroster outlets.