wiring diagram AUDI A4 1999 B5 / 1.G AC System Electrical Testing User Guide

01-132

VAG1598/11 adapter cable
LED voltage tester US 1115
Test
step VAG1598
socket Test of
Test
conditions
- additional
steps Specified values
Corrective action
5.8 13 + 12 "AC compressor
intervention" output
Engine
running - LED in voltage
tester does not come
on - Determine and rectify short
circuit to ground using wiring
diagram.
- Rectify cut-off condition for A/C
compressor in ECM.
- Rectify cut-off condition for A/C
compressor in TCM -J217-.
5.9 13 + 51 "Engine temperature
too high" signal Engine
running - LED in voltage
tester does not come
on - Determine and rectify short
circuit to ground using wiring
diagram.
- Rectify cut-off condition for A/C
compressor in Instrument Cluster.
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01-133
Test No. 6 (A/C Clutch Relay J44, actuation of Coolant Fan V7 stage 1) VAG1598/12 adapter cable Measuring range: Amperage (20 amps (A))
Test
step VAG1598
socket Test of
Test
conditions
- additional
steps Specified values
Corrective action
6.1 8 + 14 A/C Clutch
Relay -
J44-
Engine
running - less than 1 A
- Compressor
engaged and
running. - Determine and rectify open circuit or short circuit to
positive in wiring/connections between A/C Clutch -
N25-, -J44- and -E87- using wiring diagram.
- A/C Refrigerant Low Pressure Switch -F73- open,
test page 01
-131

- Replace -J44-.
- Repair or replace A/C Clutch -N25- page 87
-85
.
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01-134

VAG1598/12 adapter cable Measuring range: Amperage (20 amps (A))
Test
step VAG1598
socket Test of
Test
conditions
- additional
steps Specified
values Corrective action
6.2 16 + 14 Control of Coolant Fan
control (FC) relay -J26- (for
stage 1 operation of
Coolant Fan -V7-)
Engine
running - less than
1 A
- Fan runs
in stage 1. - Determine and rectify open circuit or short
circuit to positive in wiring/connections
between -J26- and -E87- using wiring
diagram.
- Check -V7- Repair Group 19
Note:
Testing operation of coolant fan via refrigerant high pressure switch F23 page 87
-64
.
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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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01-138
Test No. 2 (Temperature Sensors -G17-, -G56-, -G89-, G191-, G192-. ) Adapter cable VAG1598/11
Measuring range: Resistance measurement (20 K / 200 K ) Test
Step VAG1598
socket Test of
Test conditions
- additional work Specified Value
Corrective action
2.1 to
2.3 page 01
-122

2.4 26 + 49 Sender for outlet
temperature,
center -G191-. - Measure
temperature at
mounting location
of sensor. - Dependant on temperature
at mounting location of
sensor - Diagnose and repair short,
open circuit or contact
resistance in
wiring/connections using
wiring diagram.
2.5 25 + 49 Sender for outlet
temperature, floor
outlet -G192-. - Measure
temperature at
mounting location
of sensor. Confirm using
temperature/resistance
table page 01
-139

- Replace sensor(s)
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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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01-141
Test No. 4 (air/temperature distribution flap motors and related potentiometers) Adapter cable VAG1598/12
Measuring range: Resistance measurement (20 K ) Test
Step VAG1598
socket Test of
Test
conditions
- additional
work Specified
Value Corrective action
4.1 to
4.6 page 01
-126

4.7 14 +
2
3
4
5 Short to ground of wiring to
flap motors -V68-, -V85-, -
V70-, -V71-
Ignition
off - Ohm
- Diagnose and repair short to ground in
wiring/connections using wiring diagram.
Adapter cable VAG1598/12
Measuring range: Voltage measurement (20 V)
Test
Step VAG1598
socket Test of
Test
conditions
- additional
work Specified
Value Corrective action
4.8 14 + 2
3 Short to positive of wiring to
flap motors -V68-, -V85-, -
Ignition
on - less than
1V - Diagnose and repair short to positive
in wiring/connections using wiring
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4
5 V70-, -V71-
diagram.
Note:
If DTC's for several flap motors are shown and malfunction is not determined in test 4, check wiring for short between
individual flap motors (e.g. -V85- and -V70-, measured value between sockets 3 and 4 must be Ohm).
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01-143

A/C control head -E87- connected to test box with adapter cable VAG1598/11
LED Voltage tester VAG1527B
Test
Step VAG1598
socket Test of
Test conditions
- additional work Specified
Value Corrective action
5.8 14 + 12 "A/C compressor
intervention"
output.
Engine
running. A/C
compressor
off
- Switch on A/C
compressor - LED lights
up


- LED lights
up slightly
dimmer. - Diagnose and repair open or short circuit in
wiring/connections using wiring diagram.
- Diagnose and eliminate A/C compressor
cut-off condition(s) from Engine Control
Module (ECM) or Transmission Control
Module (TCM)
- Diagnose and repair short circuit to ground
in wiring/connections using wiring diagram.
5.9 Ground
and
51 "Engine
temperature too
high" signal. Engine
running. - LED lights
up. - Diagnose and repair short circuit to ground
in wiring/connections using wiring diagram.
- Diagnose and eliminate A/C compressor
cut-off condition from Instrument cluster
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