Elements of the automatic heating system (HAU) (Mercedes-Benz E-Class W210)

Interior temperature sensor is installed in the front interior light. To quickly record temperature fluctuations in the interior, the interior air is constantly pumped through the sensor - for this purpose, a small fan is installed on it. The interior temperature is constantly maintained at the set value regardless of the vehicle speed.

Radiator temperature sensors are installed on the heater body under the instrument panel behind each of the two radiators. They determine the temperature directly behind the radiators and transmit the information to the automatic control unit. The latter processes signals from the cabin temperature sensor and from each of the sensors on the radiators with a given ratio. This is how the actual temperature in the cabin is determined. To perform this or that adjustment, the actual value is compared with the set value. The heater fan is used to increase heating. The fan speed is regulated by the electronic control unit.

Cleaning filter of the air entering the passenger compartment from dust. It filters the incoming and recirculated air. The replaceable filter element is located directly in front of the fan. Depending on the size of the dust particles, the filtration rate can reach 100%. The filter, made of polycarbonate, also performs electrostatic filtration. It is insensitive to water and has low air resistance. The filter cannot be cleaned.

Exhaust air from the passenger compartment through the opening behind the rear shelf passes between the body and the plastic trim behind the right rear trim of the trunk. Through the ventilation flap under the right side of the shock absorber strut it is discharged to the outside.