Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...
Air conditioner with refrigerant R134a - Edition 11.2018
3.6.10
Refrigerant temperature sender - G454-
The refrigerant temperature sender (with a temperature-sensitive
resistor) is installed, for example, in the high-pressure line near
the air conditioner compressor (only for certain vehicles manu‐
factured within a specific period, e.g. on Audi Q7 2007>).
In the refrigerant circuit, there is a direct relationship between
temperature and pressure. If there is insufficient refrigerant in the
circuit, the temperature in the refrigerant circuit during air condi‐
tioner operation will increase more sharply than envisaged for this
pressure.
Note
♦ Installed e.g. in Audi Q7 with certain engines ⇒ Heating, air
conditioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific
Workshop Manual) and ⇒ Current flow diagrams, Electrical
fault finding and Fitting locations.
♦ The operating and display unit ( Climatronic control unit -
J255- ) evaluates the pressure and the temperature in the
refrigerant circuit and switches off the air conditioner com‐
pressor if the temperature increases above the value stored
for this pressure ⇒ Heating, air conditioning; Rep. gr. 87 ;
Refrigerant circuit (vehicle-specific Workshop Manual) and ⇒
Vehicle diagnostic tester (“Self-diagnosis” or “Guided Fault
Finding” function for air conditioner).
3.7
Electrical components not installed in
refrigerant circuit
⇒ “3.7.1 Radiator fan control unit J293 ”, page 65
3.7.1
Radiator fan control unit - J293-
This control unit switches the magnetic clutch and thus the air
conditioner compressor on and off. It switches the radiator fans
and calculates the pressure in the refrigerant circuit on vehicles
with a high-pressure sender - G65- . Refer to ⇒ Current flow dia‐
grams, Electrical fault finding and Fitting locations and ⇒ Heating,
air conditioning; Rep. gr. 87 ; Refrigerant circuit (vehicle-specific
Workshop Manual).
3.8
Pressures and temperatures in refriger‐
ant circuit
Caution
♦ When working on the refrigerant circuit, observe generally
valid safety precautions and pressure vessel regulations.
The pressures and temperatures in the refrigerant circuit depend
on the instantaneous operating statuses (e.g. engine speed, ra‐
diator fan speed 1, 2, or 3, engine temperature, air conditioner
compressor on or off) as well as environmental influences (e.g.
ambient temperature, humidity, required cooling output).
3. General information on refrigerant circuit
65
English 
