Heating and ventilation system — general information (Audi A4 B5)

1. The heating and ventilation system consists of an adjustable fan motor (installed under the front panel), face deflectors in the center and along the edges of the panel and air ducts to the feet of the front passengers.

2. The heater control unit is mounted on the front panel, from where the dampers for mixing cold and hot air flowing in different directions of the heating and ventilation system are controlled. The dampers are located in the air distributor housing, which distributes air flows to various air ducts and deflectors.

3. Cold air enters the system through a grille in the rear of the engine compartment. If required, the flow is amplified by a fan and supplied further depending on the position of the controls. The exhaust air exits through air ducts in the rear of the body. If cooling is required, cold air is passed through the heater radiator, through which, in turn, coolant flows.

4. The outside air intake can be blocked, which can be useful if you don't want to smell the outside air. This is achieved by setting the fan motor switch to the "O" position or by operating the recirculation handle (depending on the model). This mode cannot be used for a long time, since the lack of flow ventilation has a harmful effect on the body.