ignition AUDI A4 1997 B5 / 1.G AC System Electrical Testing Workshop Manual

01-116

VAG1598 test box, connecting


- Switch off ignition.

- Remove A/C control head -E87- and disconnect
all connectors, -A-, -B-, -C- and -D- page 87
-
120
.

Notes: - Connect VAG1598/11 and 12 adapter cables to corresponding
connectors of the vehicle wiring harness (to -E87-).
- Connect VAG1598 test box to the respective adapter cable for
performing measurements.
Do not connect -E87-. When using VAG1598/12 adapter cable, the terminal assignment of
the sockets is identical with the terminal assignment of -E87-. When using VAG1598/11 adapter cable, the terminal assignment of
the sockets is not identical to the terminal assignment of -E87-
terminal assignment, page 01
-117
.
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01-120
Test No. 1 (A/C control head -E87- voltage supply, ground connection and illumination) VAG1598/12 adapter cable Measuring range: Voltage measurement (20 V)
Test
step VAG1598
socket Test of
Test
conditions
- additional
steps Specified
values Corrective action
1.1 9 + 14 Terminal 75x and ground
connection at -E87-
Ignition on - approx.
battery voltage - Repair voltage supply or ground
connection using wiring diagram.
1.2 9 + 15 Ground connection at -
E87- Ignition on - approx.
battery voltage - Repair ground connection using
wiring diagram.
VAG1598/11 adapter cable Measuring range: Resistance measurement (200 ohm)
Test
step VAG1598
socket Test of
Test
conditions
- additional
steps Specified
values Corrective action
1.3 49 + 52 Ground connection at
-E87-
- less than 20
W - Repair ground connection using
wiring diagram.
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01-121

VAG1598/12 adapter cable Measuring range: Voltage measurement (20 V)
Test
step VAG1598
socket Test of
Test
conditions
- additional
steps Specified values
Corrective action
1.4 13 and
ground Terminal 30
at E87
Ignition off - approx. battery voltage - Repair voltage supply using
wiring diagram.
1.5 7 and
ground Terminal 58
at E87 Ignition on Parking
lights on - approx. battery voltage - Repair voltage supply using
wiring diagram.
1.6 7 and
ground Terminal 58
at E87 Ignition on Parking
lights on - less than 2 V - Rectify short circuit to positive
using wiring diagram.
1.7 45 and
ground Terminal 58D
at E87 Ignition on Parking
lights on - 0 to 12 V (depends on
setting of illumination
rheostat) - Determine and rectify open circuit
or short circuit using wiring
diagram.
1.8 45 and
ground Terminal 58D
at E87 Ignition on Parking
lights off - less than 2 V - Rectify short circuit to positive
using wiring diagram.
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01-124
Test No. 3 (Fresh Air Blower V2 and Control module for fresh air blower J126) VAG1598/11 adapter cable Measuring range: Voltage measurement (20 V)
Test
step VAG1598
socket Test of
Test
conditions
- additional
steps Specified
values Corrective action
3.1 16 and
ground Control module
for fresh air
blower J126
Ignition
on - Voltage less
than 5 V
- Blower does
not run. - Determine and rectify short circuit to positive in
wiring/connections between J126 and -E87-
using wiring diagram.
- Replace J126
3.2 14 and
ground Voltage supply for
Fresh Air Blower
V2 Ignition
on - approx.
battery
voltage - Repair voltage supply using wiring diagram.
3.3 11 and
ground Voltage supply for
J126 (via V2) Ignition
on - approx.
battery
voltage
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01-125

VAG1598/11 adapter cable
LED voltage tester US 1115
Test
step VAG1598
socket Test of
Test
conditions
- additional
steps Specified values
Corrective action
3.4 13 + 16 Control module for
fresh air blower -
J126-
Ignition
on - LED in voltage
tester comes on
- Fresh air blower
runs - Determine and rectify open circuit in
wiring/connections between -J126- and -
E87-.
- Check Fresh Air Blower V2
operates freely.
- Replace -J126-.
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01-131

VAG1598/11 adapter cable Measuring range: Voltage measurement (20 V)
Test
step VAG1598
socket Test of
Test
conditions
- additional
steps Specified
values Corrective action
5.6 3 + ground A/C Refrigerant Low
Pressure Switch -F73-
Ignition on- approx.
battery voltage - Determine and rectify open circuit in
voltage supply using wiring diagram.
- -F73- malfunction page 87
-66
- Refrigerant circuit empty, refrigerant
system pressure test page 87
-190

VAG1598/11 adapter cable Measuring range: Amperage (20 amps (A))
Test
step VAG1598
socket Test of
Test
conditions
- additional
steps Specified
values Corrective action
5.7 44 +
ground Interior
Temperature
Sensor Fan -V42-
Ignition
on - less than
1 A
- Blower
V42 runs - Determine and rectify open circuit, short circuit to
positive/ground in the wiring/connections between
V42 and -E87- using wiring diagram.
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01-135
Electrical testing, 1997

Note:
Electrical testing, 1996 page 01
-119
.
Notes:

VAG1598 test box must not be connected to A/C control head -E87- when performing On Board Diagnostic with VAG1551
Scan Tool (ST)
Further notes, test requirements, connecting adapter cables and test equipment page 01
-115
.
From m.y. 1997, do not connect VAG1598 test box to -E87- for test steps 1.1 through 5.7. (Test box only to be connected
for test steps 5.8, 5.9 and 5.10). Test
number Component(s) tested:
Page
1
- A/C control head -E87-, voltage supply and ground connection
- Signal for time span ignition off Page 01
-
136

2
- Temperature sensors -G17-, G56, -G89- -G191- and -G192- Page 01
-
138

3
- Fresh air blower -V2-, Control module for fresh air blower -J126- Page 01
-
140

4
- Air/temperature distribution flap motors and related potentiometers (-V68-/-G92-, -V70-/-
G112-, -V71-/-G113-, -V85-/-G114-) Page 01
-
141

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01-136
Test No. 1 (A/C control head -E87- voltage supply, ground connection) Adapter cable VAG1598/12
Measuring range: Voltage measurement (20 V)
Test
Step VAG1598
socket Test of
Test
conditions
- additional
steps Specified value
Corrective action
1.1 9 + 14 Terminal 15 and ground
connection at -E87-
Ignition on - approx.
battery voltage. - Repair voltage supply or ground
connection using wiring diagram.
1.2 9 + 15 terminal 15 and ground
connection at -E87- Ignition on - approx.
battery voltage. - Repair ground connection using
wiring diagram.
1.3 page 01
-120

1.4 Not for 1997. Terminal 30 no longer connected
1.5 to
1.8 These test steps are conducted only for vehicles up to and including m.y. 1997 (A/C control head with Part. No.
8D0 820 043 and Part No. 8L0 820 043 up to Part No. index letter "C").
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01-137

Adapter cable VAG1598/11
LED Voltage tester VAG1527B
Test
Step VAG1598
socket Test of
Test
conditions
- additional
work Specified Value
Corrective action
1.9 term.15 1) +
33 Signal for time
span ignition
off
Ignition
on - LED lights up - Diagnose and repair short or open
circuit in wiring/connections using wiring
diagram.
1.10 term.15 1) +
33 Signal for time
span ignition
off Ignition
on



- Start
engine. - LED lights up



- LED flickers briefly
(time signal) and then
lights up again - Diagnose and repair short or open
circuit in wiring/connections using wiring
diagram.
- Check signal from instrument cluster.
1) Terminal 15 (ignition) is available at -E87- connector -D-, terminal -9-.
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01-140
Test No. 3 (Fresh Air Blower -V2- and Control Module for Fresh Air Blower -J126-) Adapter cable VAG1598/11
Measuring range: Voltage measurement (20 V)
Test Step
VAG1598 socket
Test of
Test conditions
- additional work Specified Value
Corrective action
3.1 to 3.3 page 01
-124

Adapter cable VAG1598/11
LED Voltage tester VAG1527B
Test
step VAG1598
socket Test of
Test
conditions
- additional
work Specified
Value Corrective action
3.4 14 + 16 Control module for
fresh air blower -
J126-
Ignition
on - LED lights up - Diagnose and repair open circuit in
wiring between -J126- and -E87- using
wiring diagram.
- Fresh Air Blower -V2- check for ease of
movement.

- Fresh air
blower running. - Replace -J126-.
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