Function

Function
The automatic air conditioning (auto A/C) has an electronically controlled cooling, heating and ventilation system and can be summarized with the partial function described below

- Ventilation
The ventilation provide for the air flow through the passenger compartment. The air flow is supported by the automatic A/C blower or the rear A/C blower in normal operation when the vehicle is standing still or to increase the quantity of air The air is distributed in the vehicle passenger compartment by the air distribution flaps.


NOTE: In order to prevent the windows from fogging up the front footwell flaps and rear footwell flaps are opened completely for 30 seconds after switching on the ignition.
On vehicles with rear air conditioning only the front footwell flaps are opened the rear footwell flaps remain closed.


- Automatic A/C temperature control
The desired temperature is achieved or maintained by cooling or heating the air. Precise temperature control is achieved by reading in various temperature sensors.

- Automatic A/C control
The electronic control for the automatic A/C is accomplished with various control modules connected With one another by the passenger compartment bus (CAN class B). The CAN data bus is a bi-directional bus, i.e. each connected element can receive and transmit information

- Automatic A/C pushbutton control module
The automatic A/C can be controlled by the driver with the various function buttons. In addition the pushbutton control module reads in the signals from various sensors, processes the signal and controls the components in the automatic A/C system.

- Rear air conditioning pushbutton control module
The rear air conditioning can be controlled by the rear passengers with the various function buttons. In addition the pushbutton control module read in the signals from various sensors directly processes the signal and controls the components in the air conditioning system.

- Heater circuit
The coolant is heated by the engine. Then the heated coolant flows through the heater core (on vehicles with rear air conditioning "code 582" also through the rear heater core ), where the heat is transferred to the passenger compartment air The coolant returns to the coolant pump through the heater return line.

- Refrigerant circuit
The A/C compressor compressor the gaseous refrigerant which heats up and flows into the condenser where it is cooled. After purification in the receiver/ drier the liquid refrigerant 1.5 sprayed into the evaporator (on vehicles with rear air conditioning into the rear AC evaporator) The refrigerant evaporates and cools down. The A/C compressor sucks in the refrigerant which has again become gaseous due to the heat absorbed

- Residual engine heat utilization system
The residual engine heat utilization system makes it possible to heat the vehicles even with the ignition OFF. The system uses the residual engine heat for this purpose and transfers it into the vehicle passenger compartment with the blower.