Fresh air for heating enters the passenger compartment through an air inlet under the windshield. In this case, the air flows around the heating radiator and is distributed through various flaps to individual nozzles. If the heating is set to "warm" (warm), then the heating valves in the engine compartment open to access the heat exchanger. The heat exchanger is located in the heating radiator and is heated by hot coolant. Passing by the hot panels of the heat exchanger, fresh air is heated and then enters the car interior.
The temperature in the car interior can be set in the left or right half of the cabin, depending on the position of the rotary control. The electronic control unit in the heating device regulates the opening time of the heating valves depending on the interior temperature. Behind the heat exchanger and in the maintenance device are internal temperature sensors. Thus, the temperature in the car is kept approximately constant, regardless of the speed of the car and the outside temperature.
A four-stage heating fan is used to enhance the heating power. In order for the airflow at individual stages to occur at different speeds, switching to additional resistances is provided. Thanks to them, the current flowing to the fan motor decreases, and the airflow is slower. At the highest blowing speed level, additional resistances are disabled.
If the heating system has an additional dust filter, dust, pollen, air pollution and other microparticles are captured. Switching can completely close the access of air from outside. The air is then regulated through a special air filter in the passenger compartment.