Heating and Air Conditioning: Description and Operation

This is a"Blend Air" type of system. Air enters through the cowl openings and flows through the evaporator and heater core. The blend-air door position determines the temperature of the discharge air, and is controlled by the temperature lever and control cable. The heater control valve is controlled by this lever, also, through a vacuum switch mounted on the control. The Air flow is directed by a series of vacuum-operated doors which is determined by the position of the mode lever.