External air through the air intake in the rear of the hood enters independently or additionally with the help of a fan into the vehicle interior. When the heating is turned on, the damper opens the way for air flow through the heater core, which looks like a small radiator. The passing air is heated by the radiator fins.
In order to increase the power of the heater, a four-stage heater fan is used.
Late model fan elements
1 - fan; 2 - body; 3 - air cleaner; 4 - air duct.