air condition AUDI A4 1999 B5 / 1.G AC System Electrical Testing Workshop Manual

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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01-122
Test No. 2 (temperature sensors G17, G56 and G89) VAG1598/11 adapter cable Measuring range: Resistance measurement (20 kohm)
Test
step VAG1598
socket Test of
Test conditions
- additional steps Specified values
Corrective action
2.1 48 + 52 Outside Air
Temperature
Sensor G17
Measure
temperature at
mounting location
of sensor - resistance table, page 01
-
123
(Resistance values
depend on measured
temperatures at mounting
location of sensor(s)
- Determine and rectify
short circuit, open circuit
in wiring or contact
resistance using wiring
diagram.
- Replace applicable
temperature sensor
page 87
-106

2.2 50 + 52 Instrument Panel
Interior
Temperature
Sensor G56
Measure
temperature at
mounting location
of sensor
2.3 47 + 52 Fresh Air Intake
Duct Temperature
Sensor G89 Measure
temperature at
mounting location
of sensor
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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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01-126
Test No. 4 (air/temperature distribution flap motors and related potentiometers) VAG1598/11 adapter cable Measuring range: Resistance measurement (20 kilo ohm)
Test
step VAG1598
socket Test of
Test
conditions
- additional
steps Specified values
Corrective action
4.1 52 +

28
29
37
30 Potentiometer
(in flap motor)
-G92- (-V68-)
-G112- (-V70-
)
-G113- (-V71-
)
-G114- (-V85-
)
- greater than 0.1kW and less
than 5.7kW (depends on
position of flap motor) - Determine and rectify open circuit
in wiring, contact resistance or short
circuit using wiring diagram.
- Replace applicable flap motor
page 87
-106
.
4.2 8 +

28
29
37
30 Potentiometer
(in flap motor)
-G92- (-V68-)
-G112- (-V70-
)
-G113- (-V71-
)
-G114- (-V85-
)
- greater than 0.1kW and less
than 5.7kW (depends on
position of flap motor)
Notes:

Potentiometer resistance (Specified values: 3.6 k to 5.7 k between flap motor terminal 3 and 4) can only be measured
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01-127

VAG1598/12 adapter cable Measuring range: Resistance measurement (200 ohm)
Test
step VAG1598
socket Test of
Test
conditions
- additional
steps Specified
values Corrective action
4.3 2 + 10 Temperature Regulator
Flap Motor -V68- 20 W to 100
W - Determine and rectify open circuit in
wiring, contact resistance or short circuit
using wiring diagram.
- Replace applicable flap motor page
87
-106
.
4.4 4 + 12 Central Flap Motor -V70- 20 W to 100
W
4.5 5 + 13 Air Flow Flap Motor -V71- 20 W to 100
W
4.6 3 + 11 Footwell/Defroster Flap
Motor -V85- 20 W to 100
W
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01-128
Test No. 5 (A/C Compressor Speed Sensor -G111-, refrigerant pressure switches -F118-, -F73- and Interior
Temperature Sensor Fan -V42-)
Note:
Electrical test steps 5.1 to 5.4 do not apply to vehicles equipped with Nippondenso compressors (A/C compressor speed
sensor G111 is not installed on Nippondenso compressors). VAG1598/11 adapter cable Measuring range: Resistance measurement (20 kilo ohm)
Test
step VAG1598
socket Test of
Test
conditions
- additional
steps Specified
values Corrective action
5.1 5 + 49 A/C Compressor
Speed Sender -G111-
- 0.8 kW to
1.5 kW - Determine and rectify open circuit in
wiring, contact resistance or short circuit
using wiring diagram.
- Replace -G111- page 87
-63
.
5.2 5 and
ground A/C Compressor
Speed Sender -G111-
- greater
than
2 kW - Determine and rectify short circuit using
wiring diagram.
- Replace -G111- page 87
-63
.
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01-129

VAG1598/11 adapter cable Measuring range: Voltage measurement (20 V)
Test
step VAG1598
socket Test of
Test conditions
- additional steps Specified
values Corrective action
5.3 5 and
ground A/C Compressor Speed
Sender -G111-
Engine running Compressor not
running - less than 1
V - Determine and rectify short
circuit using wiring diagram.
VAG1598/11 adapter cable Measuring range: Voltage measurement (2 V)
Note: additional test steps before proceeding with this test. Test
step VAG1598
socket Test of
Test conditions
- additional steps Specified values
Corrective
action
5.4 5 and
ground A/C Compressor
Speed Sender -
G111-
Engine running Compressor running
- Relay for A/C Clutch removed
- Bridge terminals 30 + 87 at relay
connector base (A/C Clutch
switched on) - greater than 0.05 V
(depends on engine
speed) - Replace -G111-
page 87
-63
.
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01-130

VAG1598/11 adapter cable Measuring range: Resistance measurement (200 ohm)
Test
step VAG1598
socket Test of
Test
conditions
- additional
steps Specified
values Corrective action
5.5 2 + 49 A/C Refrigerant High
Pressure Switch -F118-
- less than
20 W - Determine and rectify open circuit in
wiring or contact resistance using wiring
diagram.1)
- Replace -F118- page 87
-25
.
1)If code 1 "high-pressure switch -F118 open" is displayed in measuring value block 1 as a compressor cut-off condition: -Test
connections to -F118- for loose terminal using wiring diagram. -Test actuation of Coolant Fan V7 stage 1 Output Diagnostic Test Mode, page 01
-42
. Test actuation of Coolant Fan V7 stage 2 page 01
-42
. If no fault can be determined, check for
refrigerant system malfunction, refrigerant system pressure test page 87
-190
.
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