coolant temperature AUDI A4 1998 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

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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

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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).
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