The automatic air conditioning is an electronically controlled cooling, heating and ventilation system for keeping the desired interior temperature constant.
The automatic air conditioning starts running when the engine is started and operates according to the so-called "reheat" principle. This means:
The A/C compressor operates continuously at outdoor temperatures above 1 °C and cools down the cold incoming air. This effect serves primarily for comfort because cooling simultaneously dries the air which is a prerequisite for a pleasant interior atmosphere. After the cooling process the dehydrated air is heated up to the set temperature in the heater core.
When the EC button is pressed, the cooling is switched off.
In order to prevent the windows from fogging up, the footwell flaps are opened completely for 30 seconds after switching on the ignition.
Heating mode
The heater core temperature sensor measures the air temperature at the heater core while the interior air temperature sensor determines the corresponding interior temperature.
In addition the outdoor air temperature is determined by the outdoor air temperature sensor.
The electronic circuitry in the pushbutton control module compares the various readings with the desired temperature set on the temperature buttons.
The electronic circuitry read justs the automatic air conditioning or keeps the present settings constant as required.