GF83.40-P-3012LE Component Description For Automatic Air Conditioning Control Unit

GF83.40-P-3012LE Component Description For Automatic Air Conditioning Control Unit

Component Identification:

Location
The AAC [KLA] control unit is located on the front side of the air conditioner housing on the passenger side.

Task
The AAC [KLA] control unit has the following tasks:
^ Control of the vehicle climate control
^ Reading in of sensors and signals
^ Evaluation of input factors
^ Actuation of components

Control of the vehicle climate control
The AAC [KLA] control unit is the master control unit for the climate control of the vehicle interior and controls or regulates the following functions:
- Comfort automatic air conditioning (C-AAC [K-KLA]) On/Off
- Overall automatic system
- Regulation of interior temperature, blower output and air distribution, separately for the left and right vehicle sides
- Adaptation of the footwell temperature
- Adjustment of the air flow intensity
- Defrosting
- Open/close recirculated air
- Residual engine heat utilization system
- Coupling of all setting zones with driver zone
- Stationary heater climate control function
(with code (228) Stationary heater)
- Remote control of rear automatic air conditioning
(with code (582) Rear air conditioning)

The comfort automatic air conditioning functions are operated via the upper control panel control unit (N72/1) or the front central operating unit (A40/9).
With code (582) Rear air conditioning, the request from the rear air conditioning control unit (N22/4) is sent to the COMAND control unit (A40/3) via the telematics CAN (CAN A), to the central gateway control unit (N93) via the central CAN (CAN F) and from there, to the AAC control unit via the interior CAN (CAN B).

Reading in of sensors and signals
The input factors are read in with the following connections:
^ Direct line
^ Air conditioning bus (ACB)
^ Interior CAN

Direct line
The signals from the following components are read via a direct line:
- In-car temperature sensor (B10/4)
- Evaporator temperature sensor (B10/6)
- Left side outlet temperature sensor (B10/31)
- Right side outlet temperature sensor (B10/32)
- Left footwell temperature sensor (B10/35)
- Right footwell temperature sensor (B10/36)
- Refrigerant pressure sensor (B12)
- Left side air outlet potentiometer (R41/1)
- Right side air outlet potentiometer (R41/2)
- Left front center air outlet potentiometer (R41/3r1)
- Right front center air outlet potentiometer (R41/3r2)

In addition with code (582) Rear air conditioning:
- Left rear air conditioning heat exchanger temperature sensor (B10/9)
- Right rear air conditioning heat exchanger temperature sensor (B10/10)
- Rear air conditioning evaporator temperature sensor (B10/11)
- Left rear center nozzle potentiometer (R41/4r1) (model 221)
- Right rear center nozzle potentiometer (R41/4r2) (model 221)

AC bus
The following sensors are read in via the A/C bus:
- AAC multifunction sensor (B31/1)
- AAC [KLA] 4-way sun sensor (B32/2)

Interior CAN
The signals are read in by the AAC [KLA] control unit via the interior CAN.
The functions resulting therefrom are described in the corresponding function descriptions (see block diagram or function schematic).

Evaluation of input factors
The input factors that have been read in are evaluated by the integrated microprocessor and the affected components are then actuated.

Actuation of components
The actuation of the components takes place via the following connections:
^ Direct line
^ Climate control LIN (LIN B8)
^ Interior CAN

Direct line
The following components are actuated:
- Refrigerant compressor (A9)

In addition with code (582) Rear air conditioning:
- Delivery unit for rear heating system (A31/1)
- Rear air conditioning electronic blower regulator (N29/2)
- Rear AC refrigerant shutoff valve (Y67)

Climate control LIN

The following components are actuated via climate control LIN:
- Blower regulator (A32n1)
- Fresh air/air recirculation flaps actuator motor (M2/5)
- Left defroster vent flap actuator motor (M2/8)
- Right defroster vent flap actuator motor (M2/9)
- Left footwell flap actuator motor (M2/10)
- Right footwell flap actuator motor (M2/11)
- Left center air flap actuator motor (M2/12)
- Right center air flap actuator motor (M2/13)
- Left side outlet flap actuator motor (M2/17)
- Right side outlet flap actuator motor (M2/18)
- Upper left blend air flap actuator motor (M2/30)
- Lower left blend air flap actuator motor (M2/31)
- Upper right blend air flap actuator motor (M2/32)
- Lower right blend air flap actuator motor (M2/33)
- Left rear center air vent actuator motor (M16/19)
(with code (582) Rear air conditioning)
- Right rear center air vent actuator motor (M16/20)
(with code (582) Rear air conditioning)
- Left B-pillar air distribution actuator motor (M16/33)
(model 221)
- Right B-pillar air distribution actuator motor (M16/34)
(model 221)
- PTC heater booster (R22/3) (with diesel engine)

Interior CAN
The signals are transmitted by the AAC [KLA] control unit via the interior CAN.
The functions resulting therefrom are described in the corresponding function descriptions (see block diagram or function schematic).