Audi A3 1997 Manual page 26

Audi A3 1997 ➤
Heating, Air Conditioner - Edition 06.2000
- when thermoswitch -F18 is closed.
-when AC pressure switch -F129 (switch between the contacts 3 and 4) is closed.
- as soon as a refrigerant circuit pressure in excess of 16 bar is calculated by -J293 on the basis of a signal
from high-pressure sensor -G65.
◆ In vehicles with map-controlled cooling the radiator fans are switched on and off by the engine control unit
dependent on the refrigerant temperature.
◆ In vehicles with 8l KW diesel engine and 132 KW petrol engine the engine control unit fans are also activated
dependent on the refrigerant temperature or after switching of the ignition (as radiator fan runout).
=> Relevant Workshop Manual Injection and Ignition system; Repair group 01
Indicated on display
At the same time the output "air conditioner
compressor cut-in" is also activated.
Notes:
◆ Only check this output "Air conditioner compressor cut-in" in the event of a complaint (check =>Page
23 ).
◆ In operating and display units with two displays the output "air conditioner compressor cut-in" is connected
to connector -C- contact -12-.
◆ With operating and display units with one display the output "air conditioner compressor cut-in" is connected
to connector -C- contact -1-.
◆ The "ECON key" is the key with the frost symbol in the model of the -E87 with two displays.
◆ The engine control unit uses the "AC compressor cut-in" signal to compensate for the brief increase in engine
load when the compressor is switched on.
=> Relevant Workshop Manual Injection and Ignition system
◆ The air conditioner compressor can be switched off by the engine control unit and/or control unit for automatic
gearbox -J217 via the output/input ("Air conditioner compressor cut-in") (=> Reading measured value block,
Page 31 display group 01, Injection and Ignition system Workshop Manual and Automatic Gearbox
Workshop Manual).
◆ To test, e.g. read out measured value block of ignition and injection system control unit with engine running
while switching the compressor on and off (by actuating the "key with frost symbol") or connect test box
V.A.G 1598.
Indicated on display
Two-way valve for refrigerant shut-
off valve -N147
Notes:
◆ The control element "two-way valve -N147" is only activated with an operating and display unit -E87 with
one display which is coded to an engine with map- controlled engine cooling.
20
01 - Self-diagnosis, Electrical check
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Desired function
- The two-way valve -N147 is switch‐
ed on and off in 2 second intervals.
The refrigerant shut-off valve closes
and opens in 2 second intervals
(blocks the flow of refrigerant through
the heat exchanger of the air condi‐
tioning unit).
Desired function
- The operating and display unit -E87 output is
switched from 0Vto 12V at 2 sec. intervals
(check for example by switching the compressor
on and off via the "ECON button" while the
measured value block for the engine control unit
is being displayed).
=> Relevant Workshop Manual Injection and Ig‐
nition system; Repair group 01
=> Relevant Workshop Manual Automatic Gear‐
box; Repair group 01
Fault remedy
Fault remedy
- Wiring between -N147 and -E87 for
open circuit or incorrect installation
according to current flow diagram.
Check two-way valve -N147 (=>
Electrical check, Page 163 )