GF83.57-D-2020H Rear Air Conditioning System Temperature Control, Function

GF83.57-D-2020H Rear Air Conditioning System Temperature Control, Function

- with CODE (HH7) Additional air conditioning in rear







S98 KLA control and operating unit
S98s2 Rear blower control button (+)
S98s3 Rear blower control button (-)
S98s7 Rear air conditioning button
S98s15 Rear temperature selection switch

The rear automatic air conditioning temperature can only be regulated via the rear temperature selection switch integrated into the KLA control and operating unit if it is switched on using the rear air conditioning button integrated into the KLA control and operating unit.
Activation of the rear automatic air conditioning system is indicated by illumination of the red light emitting diode (LED) in the rear air conditioning button.
The rear automatic air conditioning enables a pleasant interior climate to be set in the passenger or load compartment of the vehicle during different weather conditions.
The rear temperature selection switch is used to set the desired temperature in the passenger or load compartment of the vehicle, and to regulate it as a function of the interior temperature in the passenger or load compartment of the vehicle.
The temperature in the passenger or load compartment of the vehicle can be reduced by turning the rear temperature selection switch to the left. The temperature in the passenger or load compartment of the vehicle can be increased by turning the rear temperature selection switch to the right.

In addition, the KLA control and operating unit reads in the values of the following components:
- Evaporator temperature sensor (A32/2b1)
- Blend air flap potentiometer (A32/2r2)
- Rear interior air temperature sensor ventilation blower (M9/1)

The KLA control and operating unit reads in the 3 values and - depending on the specified temperature set via the rear temperature selection switch - regulates the blend air flap actuator motor (A32/2m2), the refrigerant shutoff valve (A32/2y1) with the integrated rear expansion valve and, using the refrigerant compressor control valve (A9y1) it also regulates the refrigerant compressor (A9). The blend air flap actuator motor adjusts the blend air and shutoff flap thus regulating the recirculated air flowing over the rear evaporator.
The refrigerant shutoff valve with the integrated rear expansion valve closes or opens the refrigerant feed line.

When the refrigerant shutoff valve with the integrated rear expansion valve is open, the flow of refrigerant to the rear evaporator is regulated as a function of the low pressure (gaseous) and the temperature at the rear evaporator outlet.
Actuation of the refrigerant compressor over the refrigerant compressor control valve is primarily dependent on the value of the evaporator temperature sensor; this is because the refrigerant pressure in the air conditioning system changes depending on the cooling level required in the rear evaporator, and the refrigerant compressor has to increase or reduce the refrigerant delivery rate over the refrigerant compressor control valve.

The recirculated air cannot be heated using the rear temperature selection switch.

To accelerate the increase or reduction in temperature, the rear blower control button (+) and the rear blower control button (-) which are integrated into the KLA control and operating unit can be used to adjust the output of the blower motor (A32/2m1) in 3 stages. The recirculated air is distributed over the roof air duct and the air outlets which can be swiveled and closed.