Exhaust gases, steam and gases resulting from the operation of the engine are filled into the vehicle cabin with the harmful gas coming from the environment. Breathing these harmful gases for a long time harms the health of the people inside the vehicle. Therefore, these gases need to be cleaned. The ventilation systems in the vehicles are one of the important parts of this cleaning.

What is a Ventilation System?

Harmful gases inside the vehicle cabin are cleaned with the help of ventilation. There are flaps and fins placed on the front of the cabin, and on the rear sides. Thanks to these flaps and fins, the mentioned gases are cleaned before they fill the vehicle.

Working Principle of Ventilation System

This system includes:

  • Air direction flaps,
  • Valve motors,
  • Air ducts,
  • Blowers,
  • Control panel,
  • Heating and cooling elements

When the ventilation is operated from the control panel, the air taken from outside by the electro fan is passed through the heating radiator and blown to different parts of the cabin. If the air ducts are long, blowers are used. Hot / cold adjustment can be made at any time. In this way, hot, cold or warm air fills the cabin.

Duties of the Ventilation System

  • Ensuring that the air inside the vehicle is heated,
  • To provide cooling of the air inside the vehicle,
  • To ensure the exchange and circulation of the air inside the vehicle.

Parts of Ventilation

Air Direction Valve Motors

It allows the air to be taken directly from the outside into the cabin. At the same time, it distributes the air inside the vehicle to different parts of the vehicle, either hot or cold.

There are 5 different types:

  • Intense Pressure Valve Motor
  • Air Circulation Valve Motor
  • Demisting Valve Motor
  • Hot Air Valve Motor
  • Cold Air Valve Motor

Air Direction Channels

The air produced in the ventilation system is taken into the vehicle or distributed through the ducts. For this reason, routing channels have an important place in the ventilation system.

Air ducts ensure that:

  • The air is taken from the outside into the vehicle,
  • and the air formed in the ventilation system is taken into the vehicle.

Cabin Distribution Channels

By the distribution channels taken into the cabinet, the air is distributed:

  • To the foot parts of the vehicle,
  • To the front part,
  • To the sides,
  • To the defrost outlet for demisting of windshields.


It is in every vehicle. It is the last element of the heating and ventilation system. The blowers are the final point where the air produced in the ventilation is distributed into the vehicle. It ensures that the produced air is distributed inside the vehicle at specified angles. If desired, the air flow can be increased, decreased or completely cut off by controlling it.

Since the blowers are exposed to hot / cold air currents, they are produced from durable plastic material. In this way, they do not lose their properties in temperature changes.

Ventilation / Heating Control Panel

  • Air distributor button: It allows the air in the cabin to move in the desired direction.
  • Air inlet button: It is connected to the air flap to be taken into the cabin. When the button is pressed, the way of the air to be taken in is opened. In this way, the outside air is taken into the vehicle.
  • Temperature adjustment button: It is the button that adjusts the temperature of the air to be supplied into the cabin. In classical heating systems, red performs heating and blue performs cooling.
  • Rear window demisting button: It enables the resistance on the rear window to be operated. In this way, it is used to defrost the rear window.
  • Fresh air circulation button: It provides the exchange of air inside the vehicle. It can be used after the engine is started. However, it can also be operated without any time restrictions. This provides better cooling at high temperatures.
  • Horizontal adjustment button: It is the control button that adjusts the temperature or the coldness of the air to be supplied into the cabin. In automatic systems, when the red or blue parts on the control panel are pressed, it is adjusted automatically by the control unit.

Brands shown for reference purposes only. It does not mean that it is an original product.