Audi A3 1997 Manual page 18

Audi A3 1997 ➤
Heating, Air Conditioner - Edition 06.2000
V.A.G 1551 printer
00785 3211
Dash panel temperature sensor -
G56
* Short to earth/SP
* Open circuit/short to
positive /SP
00787 3213
Temperature sensor for fresh air in‐
take duct -G89
* Short to earth/SP
* Open circuit/short to
positive /SP
Vehicles with air conditioner pressure switch -F129
V.A.G 1551 printer
00792 3224
Air conditioner pressure switch -
F129
* Short to earth /SP
Notes:
◆ High-pressure sensor -G65 will gradually replace air conditioner pressure switch -F129 (as of Model Year
1999, initially vehicles with 1.6 l engines). As of model year 2001 only high pressure switches -G65 are
installed.
◆ Radiator fan control unit -J293 versions and vehicle wiring differ for vehicles with pressure switch -F129 and
high-pressure sensor -G65.
=> Parts List
=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations
◆ Pressure switch -F129 consists of 2 switching elements:
- The compressor is switched off via contacts 1 and 2 in the event of vacuum or overpressure in the refrigerant
circuit (switch opens).
- The radiator fan is switched to the 2nd speed via contacts 3 and 4 (switch closes).
◆ If the switch between contacts 1 and 2 in pressure switch -F129 is open, this is initially recognised by
operating and display unit -E87 as overpressure in the refrigerant circuit and stored as a fault. If the measured
ambient temperature is between 0 °C and 50 °C and the switch remains open for longer than 30 seconds,
the function switches from overpressure to vacuum pressure (low-pressure switch function) =>Reading
measured value block, Page
◆ If open high-pressure switch -F129 is detected 30 times within one driving period due to a loose contact, for
example, the compressor is switched off. The compressor can be switched on again by actuating the "Com‐
pressor on" button or by switching the ignition off and on again. If this fault occurs over several driving cycles,
the compressor cannot be switched on again until the fault memory has been erased.
12
01 - Self-diagnosis, Electrical check
Possible causes of fault
▪ In the event of an -E87 with two
displays
Short circuit or open circuit be‐
tween -G56 and -E87.
Temperature sensor -G56 defec‐
tive.
▪ In the case of an -E87 with one
display:
Operating and display unit -E87 de‐
fective.
- Short circuit or open circuit be‐
tween -G89 and -E87.
Temperature sensor -G89 defec‐
tive.
Possible causes of fault
- Open circuit in wiring between -
F129 and -E87.
Actuation of radiator fan -V7 (speed
1) defective.
Condenser or radiator dirty.
Actuation of radiator fan -V7 (speed
2) from pressure switch -F129 de‐
fective.
Pressure switch -F129 defective.
Fault in refrigerant circuit (overpres‐
sure or vacuum).
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permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
31 (display group 01, compressor shut-off criteria).
Fault remedy
▪ In the event of an -E87 with two dis‐
plays
Use current flow diagram to locate
and eliminate short circuit or open cir‐
cuit
Checktemperature sensor -G56
(=>Electrical check, Page
▪ In the case of an -E87 with one dis‐
play:
Renew operating and display unit -
E87.
- Use current flow diagram to locate
and eliminate short circuit or open cir‐
cuit
Checktemperature sensor -G89
(=>Electrical check, Page
Fault remedy
- Use current flow diagram to locate
and eliminate open circuit or loose
contact.
Check the actuation of the fan -V7
(speed 1) =>Final control diagnosis,
Page 135 ).
Send vehicle to a specialist VW/Audi
air-conditioning service centre.
46 ).
46 ).