Ford Focus Service Manual: Heating and Ventilation

The heating and ventilation system has the following features:

• Controls the temperature and, during A/C operation, reduces the relative humidity of the air inside the vehicle
• Delivers heated or cooled air to maintain the vehicle interior temperature and comfort level
• Cooling or heating can be adjusted to maintain the desired temperature

The heating and ventilation system includes the following components:

• Blower motor
• Heater core and evaporator core housing
• Heater core

Blower Motor

The blower motor pulls air from the air inlet and forces it into the heater core and evaporator core housing where it is mixed and distributed. The blower motor receives battery voltage at all times when the ignition is in the RUN position, and is grounded by the blower motor switch.

Heater Core and Evaporator Core Housing

The heater core and evaporator core housing directs airflow from the blower motor through the evaporator core and heater core. All airflow from the blower motor passes through the evaporator core. The airflow is then directed through or around the heater core by an electric motor actuated temperature blend door. After passing through/around the heater core, the airflow is distributed to the selected outlet by 2 airflow mode doors. The 2 airflow mode doors are actuated by a single electric motor using a cam and gear setup.

Heater Core

The heater core receives a flow of coolant from the engine cooling system through the heater core inlet. The heater core consists of fins and tubes arranged to extract heat from the engine coolant and transfer it to air passing through the heater core. The engine coolant is then returned to the engine cooling system through the heater core outlet.

Heater Tube-to-Heater Core Joint

The heater core inlet and outlet tubes can each be separated from the heater core at the joints where they enter the core. The joints are each sealed using an O-ring seal, and are each secured with a clamp. It is not required to install new heater core inlet and outlet tubes when installing a new heater core unless they are damaged or are leaking independently from the core.