Automatic Air Conditioning, Function

GF83.40-P-0005RIAutomatic Air Conditioning, Function

Function requirements, general
^ Control functions: Circuit 15
^ Climate control: Circuit 61
^ Residual heat: Circuit 15C or circuit 15R

Automatic air conditioning, general
Automatic air conditioning with 2-zone temperature control is installed, i.e. the automatic air conditioning has separate temperature control for the left and right halves of the vehicle. Blower control takes place with 1 zone and can be operated manually or controlled automatically.

The regulation and control are carried out by the AAC [KLA] control and operating unit (N22).

The automatic air conditioning comprises the following subfunctions:
^ Function sequence, residual engine heat utilization
(without code (494) USA version)

Further partial functions are described in separate documents:
^ Heater circuit function
^ Automatic air conditioning refrigerant circuit, function
^ Ventilation system, function
^ Regulation of Automatic air conditioning, function

Additional function requirements for residual engine heat utilization
^ Circuit 15C or circuit 15R

Residual engine heat utilization function sequence
The function is switched on when the Rest button on the control and operating unit is pressed. The control and operating unit relays the request via the interior CAN to the front passenger-side SAM control unit (N10/11), which actuates the heater circulation pump (M13) directly. The coolant circulation pump delivers the coolant (residual heat) that is still warm through the heater heat exchanger.

At the same time, the control and operating unit relays the ventilation request via the AC bus to the blower regulator (A32n1), which then actuates the blower motor (A32m1) with reduced power. The air drawn in by the blower motor is routed along the heater heat exchanger and thus heated up.
The function is terminated after a specified fixed time or when the on-board power supply voltage drops below a certain value.