1996 AUDI A4 diagram

01-149

VAG1527 B Voltage Tester

A/C control head -E87- connected at test box (VAG1598/11 and /12 adapter cables)
VAG1598/11 adapter cable connected
Test
step VAG1598A
socket Test of
Test
requirements
- additional
operations Specified value
Corrective action
5.9 5) Ground
+
51 "Engine temperature
too high" signal
Engine
running
LED on
voltage tester
lights - Locate short circuit to Ground
and repair according wiring
diagram
- Eliminate A/C compressor cut-
off conditions in instrument
cluster
5) Only perform this test step for vehicles of m.y. 1997 or later
Notes:
Ignition key coding is transmitted to the A/C control head -E87- from the instrument cluster along with the coolant
temperature and the signal "engine temperature too high" when ignition is switched on for vehicles as of m.y. 1999 (data
message). Key coding can only be processed by A/C control heads -E87- with part number 8D0 820 043 after index "M."
No information can be transmitted if the coolant temperature is too high.
When ignition is switched on, A/C control head -E87- begins with the setting that was valid when the ignition was last
switched off with this key (temperature, air distribution, fresh air blower RPM).
Pa
ge 42 of 47 A/C s
ystem, electrical testin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.HA01.01.2

01-150
List of changes to electrical tests, 1998 VAG1527B voltage tester
VAG1598/11 adapter cable connected
Test
step VAG1598
sockets Test of
Test
conditions
- additional
operations Specified
value Corrective action
1.9 33 +
GND Signal for
"ignition off"
period
Ignition
switched on LED on voltage tester lights
- Repair open circuit or
short circuit according to
wiring diagram.
1.10 33 +
GND Signal for
"ignition off"
period Ignition
switched on
- Start engine.LED in voltage tester lights up
When starting engine, LED briefly
flickers in voltage tester (time signal)
and then lights constantly - Repair open circuit or
short circuit according to
wiring diagram.
- Check instrument cluster.
Note:
Test steps 1.9 and 1.10 apply only for vehicles beginning m.y. 1997 (A/C control head with Part No. 8L0 820 043 up to Part
No. index letter "C").
Pa
ge 44 of 47 A/C s
ystem, electrical testin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.HA01.01.2

01-151

Voltage test - switch multimeter to 20V measuring range
VAG1598/11 adapter cable connected
Test
step VAG1598
sockets Test of
Test conditions
- additional
operations Specified
value Corrective action
1.11 7 + GND Terminal 58s on -
E87-
Ignition switched
on Parking light
switched on 0 to 12 V
- Repair open circuit or short circuit
according to wiring diagram.
1.12 7+ GND Terminal 58s on -
E87- Ignition switched
on Parking light
switched off approx. 0
V. - Repair short to B+ according to wiring
diagram.
Notes:

Test steps 1.11 to 1.14 apply for vehicles beginning m.y. 1998 (A/C control head with Part No. 8L0 820 043 from Part No.
index letter "D").
The Ground connection can be made via connector D, terminals 14 and 15 (for example).
The voltage at terminal 58s is dependent on the adjustment of the illumination dimmer control.
Pa
ge 45 of 47 A/C s
ystem, electrical testin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.HA01.01.2

01-152

Voltage test - switch multimeter to 20V measuring range
VAG1598/11 adapter cable connected
Test
step VAG1598
sockets Test of
Test conditions
- additional
operations Specified
value Corrective action
1.13 45 +
GND Terminal 58d on -
E87-
Ignition switched
on Parking light
switched on 0 to12 V
- Repair open circuit or short circuit
according to wiring diagram.
1.14 45 +
GND Terminal 58d on -
E87- Ignition switched
on Parking light
switched off 0 to 12 V
- Repair open circuit or short circuit
according to wiring diagram.
Notes:

Test steps 1.11 - 1.14 apply for vehicles beginning m.y. 1998 (A/C control head with Part No 8L0 820 043 from Part No.
index letter "D").
The Ground connection can be made via connector D, terminals 14 and 15 (for example).
The voltage to terminal 58d is created as a square-wave signal from the instrument cluster. The brightness of the display
on A/C control head -E87- is determined by the period of activation. The multimeter will indicate the average value.
Pa
ge 46 of 47 A/C s
ystem, electrical testin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.HA01.01.2