Audi A4 2001 - Fresh Air Blower System Functionality

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2.2.7 A/C Refrigerant Low Pressure Switch -
F73-
Function
Switches off A/C compressor when there is excessive pressure
in the refrigerant circuit (approximately 2 bar).
2.2.8 High Pressure Sensor -G65-
This high pressure sensor is installed instead of A/C pressure
switch -F129- or A/C pressure/temperature sensor -G395- .
The A/C Pressure/Temperature Sensor -G395- (housing color
gray at this time) and the High Pressure Sensor -G65- (housing
color “black“ at this time) differ only in color at this time, correct
allocation must therefore be observed when replacing (part num‐
ber. Refer to Electronic Parts Catalog (ETKA). As these two
sensors emit different signals, the relevant control module can
only evaluate the signal to which it has been matched. Refer to
⇒ Heating and Air Conditioning; Rep. Gr. 87 ; Description and
Operation (vehicle-specific repair manual).
When a voltage is applied, the High pressure sensor -G65- gen‐
erates a square wave signal or a data telegram. This signal
changes along with pressure in the system.
The control modules (radiator fan control module, engine control
Front A/C display control head -E87- or Climatronic control mod‐
ule -J255- etc.) calculate the refrigerant circuit pressure and then
control the radiator fan and motor, the A/C clutch -N25- and will
change the control on the A/C compressor regulator valve -
N280- . Refer to ⇒ Heating and Air Conditioning; Rep. Gr. 87 ;
Description and Operation (vehicle-specific repair manual).
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A2 2001 ➤ , A ...
Refrigerant R134a Servicing - Edition 01.2011
2. Description and Operation 77