Main A/C-Heater System

WARNING: This page is about a different car, the 2002 Mercury Villager. However, it is still accessible from the selected car via links, so may be relevant.

Villager uses a cycling clutch, fixed orifice tube system. Compressor is cycled on and off to maintain desired cooling and prevent evaporator freezing. System uses reheat method to deliver conditioned air to passenger compartment. See Figure.

In this method, all airflow from blower passes through evaporator core where it is cooled and dehumidified. Passenger compartment temperature is then regulated by reheating a portion of this cooled, dry air and blending it with remaining cooled dry air. Temperature blending is varied by temperature blend door, which controls amount of cool airflow through or around heater core.

Fixed orifice tube, clutch cycling pressure switch, and dual pressure cut-out switch control cooling fan and system operation. Other system components include compressor, condenser, evaporator core, accumulator-drier, high pressure relief valve, main control panel and refrigerant lines.

Evaporator housing is located behind instrument panel between recirculating air duct and heater air plenum chamber. Evaporator housing assembly contains evaporator core, fresh air/recirc temperature control doors and blower motor.

Heater core housing is of a split-case design and contains heater core, air temperature control door and air distribution doors.