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

01-119
Electrical testing, 1996

Note:
Electrical testing, 1997 page 01
-135
.
Test
number Component(s) tested:
Page
1
- A/C control head -E87- voltage supply, ground connection and illumination. Page 01
-
120

2
- Temperature sensors G17, G56 and G89 Page 01
-
122

3
- Fresh Air Blower V2 and Control module for fresh air blower J126 Page 01
-
124

4
- Air/temperature distribution flap motors and related potentiometers V68/-G92-, -V70-/G112,
V71/G113 and V85/G114) Page 01
-
126

5
- A/C compressor speed sender G111
- Refrigerant pressure switches -F118- and -F73-
- Interior Temperature Sensor Fan V42
- "A/C compressor intervention" output
- "Excessive engine temperature" signal Page 01
-
128

6
- A/C Clutch Relay J44
- Actuation for coolant fan stage 1 Page 01
-
133

Pa
ge 7 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

01-129

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
.
Pa
ge 19 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

01-133
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
.
Pa
ge 23 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

5
- A/C pressure switch -F129-
- "A/C compressor intervention" output
- "Excessive engine temperature" signal
- Interior temperature sensor fan -V42- Page 01
-
142

6
- A/C clutch relay -J44-, A/C clutch -N25-, actuation
- Coolant fan -V7-, actuation Page 01
-
146

Pa
ge 26 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

01-146
Test No. 6 (A/C Clutch Relay -J44-, actuation of Coolant Fan -V7- stage 1) Adapter cable VAG1598/12 connected.
Measuring range: Amperage measurement (20 A)
Test Step
VAG1598 socket
Test of
Test conditions
- additional work Specified Value
Corrective action
6.1 + 6.2 page 01
-133

Note:
Actuation of -V7- stage 2 via A/C pressure switch -F129- page 87
-67
.
Pa
ge 38 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

01-148

Switch on test area at VAG1526 multimeter: voltage test (20 V)

VAG1598/12 adapter cable connected
Test
step VAG1598A
socket Test of
Test
requirements
- additional
operations Specified
value Corrective action
1.17
4) 8
+
14
Terminal 15 and Ground
connection at A/C control head
-E87- (power supply for A/C
clutch)
Ignition
switched on
approx.
battery
voltage - Repair power supply or
Ground connection
according to wiring
diagram
4) Only perform this test step for an A/C control head with one display.
Pa
ge 41 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