Audi A3 1997 Assembly instructions

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
Audi A3 1997 ➤
Electrical system
Edition 10.2003
Service
Service Department. Technical Information

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
List of Workshop Manual Repair GroupsList of Workshop Manual
Repair GroupsList of Workshop Manual Repair Groups
Audi A3 1997 ➤
Electrical system
Repair Group
27 - Starter, Current supply
90 - Gauges, Instruments
92 - Windscreen wipe and wash system
94 - Lights, Lamps, Switches - exterior
96 - Lights, Lamps, Switches - interior
97 - Wiring
Technical information should always be available to the foremen and mechanics, because their careful
and constant adherence to the instructions is essential to ensure vehicle road-worthiness and safety. In
addition, the normal basic safety precautions for working on motor vehicles must, as a matter of course,
be observed.
Service
All rights reserved.
No reproduction without prior agreement from publisher.
Copyright © 2010 Audi AG, Ingolstadt A0050005820

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
Contents
27 - Starter, Current supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1 Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1.1 Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1.2 Notes on battery handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1.3 Removing battery - Audi A3 up to Model Year 2000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
1.4 Removing battery - Audi A3 as of Model Year 2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
1.5 Removing battery - Audi S3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
1.6 Installing battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
1.7 Battery with magic eye . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
1.8 Visual inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
1.9 Checking electrolyte level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
1.10 No-load voltage measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
1.11 Checking specific gravity of electrolyte of all cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
1.12 Measuring voltage under load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
1.13 Charging battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
2 Removing and installing alternator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
2.1 Removing and installing alternator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
2.2 1.6 l and 1.8 l engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
2.3 1.8l turbo engine - Audi A3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
2.4 1.8l turbo engine - Audi S3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
2.5 1.9l TDI engine - distributor-type injection pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
2.6 1.9l TDI engine - UIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
2.7 Replacing voltage regulator - Bosch alternator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
2.8 Replacing voltage regulator - Valeo alternator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
2.9 Removing and installing ribbed belt pulley without free-wheel . . . . . . . . . . . . . . . . . . . . . . . .41
2.10 Removing and installing ribbed belt pulley with free-wheel . . . . . . . . . . . . . . . . . . . . . . . . . .42
3 Removing and installing starter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
3.1 Removing and installing starter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
3.2 Vehicles with 4-cylinder petrol engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
3.3 Vehicles with automatic gearbox 09A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
90 - Gauges, Instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48
1 Dash panel insert - up to Model Year 1999 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48
1.1 Dash panel insert - up to Model Year 1999 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48
1.2 "dEF" display on trip recorder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48
1.3 Removing and installing dash panel insert . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48
1.4 Assignment of dash panel insert lamps - Model Year 1997 . . . . . . . . . . . . . . . . . . . . . . . . . .49
1.5 Assignment of dash panel insert lamps - as of Model Year 1998 . . . . . . . . . . . . . . . . . . . .50
1.6 Multi-pin connectors at dash panel insert . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51
1.7 Assignment of contacts at multi-pin connectors at dash panel insert - Model Year 1997 . . 52
1.8 Assignment of contacts at multi-pin connectors at dash panel insert - as of Model Year 1998
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
1.9 Connection assignment at fuel-gauge sender . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
1.10 Terminal assignment at coolant temperature sender -G2 . . . . . . . . . . . . . . . . . . . . . . . . . .59
1.11 Radio clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60
2 Dash panel insert - as of Model Year 2000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60
2.1 Dash panel insert - as of Model Year 2000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60
2.2 "dEF" display on trip recorder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60
2.3 Removing and installing dash panel insert . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60
2.4 Multi-pin connectors at dash panel insert . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62
2.5 Assignment of contacts at multi-pin connectors at dash panel insert . . . . . . . . . . . . . . . . . .62
2.6 Terminal assignment at coolant temperature sender -G2 . . . . . . . . . . . . . . . . . . . . . . . . . .66
2.7 Radio clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .66
Audi A3 1997 ➤
Electrical system - Edition 10.2003
Contents i

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
92 - Windscreen wipe and wash system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68
1 Servicing windscreen wiper system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68
1.1 Servicing windscreen wiper system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68
1.2 Removing and installing windscreen wiper system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68
1.3 Adjusting park position of wiper blades . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71
1.4 Eliminating wiper judder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .72
2 Servicing windscreen washer system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73
2.1 Servicing windscreen washer system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73
2.2 Removing and installing washer fluid reservoir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .74
2.3 Removing and installing spray jets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75
2.4 Adjusting spray jets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76
3 Servicing rear window wipe/wash system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77
3.1 Servicing rear window wipe/wash system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77
3.2 Removing and installing rear wiper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78
3.3 Removing and installing rear wiper motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .81
3.4 Removing and installing spray jet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .84
3.5 Adjusting spray jet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .84
3.6 Adjusting park position of wiper blade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85
3.7 Eliminating rear wiper judder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85
3.8 Removing and installing washer fluid reservoir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86
4 Servicing headlight washer system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86
4.1 Servicing headlight washer system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86
4.2 Removing and installing spray jets of headlight washer system . . . . . . . . . . . . . . . . . . . . . .87
4.3 Adjusting spray jets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .88
4.4 Removing and installing washer fluid reservoir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .88
94 - Lights, Lamps, Switches - exterior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89
1 Servicing headlights - up to Model Year 2000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89
1.1 Servicing headlights - up to Model Year 2000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89
1.2 Exploded view of halogen headlight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90
1.3 Exploded view of gas-discharge headlight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .92
1.4 Removing and installing headlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95
1.5 Adjusting headlights (halogen headlights) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97
1.6 Adjusting headlights (gas-discharge headlights) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98
1.7 Preparation for headlight bulb replacement/replacement of headlight range control motor
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101
1.8 Replacing dipped beam bulb (halogen headlight) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101
1.9 Replacing main beam bulb (halogen headlight) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101
1.10 Replacing side light bulb (halogen headlight) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .102
1.11 Replacing gas-discharge lamp for dipped beam (gas-discharge headlight) . . . . . . . . . . . .103
1.12 Replacing main beam bulb (gas-discharge headlight) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .104
1.13 Replacing side light bulb (gas-discharge headlight) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .104
1.14 Replacing turn signal indicator bulb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .105
1.15 Removing and installing headlight range control motor . . . . . . . . . . . . . . . . . . . . . . . . . . . .106
1.16 Removing and installing gas-discharge lamp starter unit -N195 . . . . . . . . . . . . . . . . . . . . . .106
1.17 Installing repair set for headlight housing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .107
1.18 Resetting headlights for driving on left/ right (gas-discharge headlights) . . . . . . . . . . . . . . . .107
2 Servicing headlights - as of Model Year 2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108
2.1 Servicing headlights - as of Model Year 2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108
2.2 Exploded view of halogen headlight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .109
2.3 Exploded view of gas-discharge headlight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .111
2.4 Removing and installing headlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .114
2.5 Adjusting headlights (halogen headlights) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .116
2.6 Adjusting headlights (gas-discharge headlights) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .117
2.7 Preparation for headlight bulb replacement/replacement of headlight range control motor
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .120
Audi A3 1997 ➤
Electrical system - Edition 10.2003
ii Contents

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
2.8 Replacing dipped beam bulb (halogen headlight) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .120
2.9 Replacing main beam bulb (halogen headlight) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .120
2.10 Replacing side light bulb (halogen headlight) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .121
2.11 Replacing gas-discharge lamp for dipped beam (gas-discharge headlight) . . . . . . . . . . . .121
2.12 Replacing main beam bulb (gas-discharge headlight) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .122
2.13 Replacing side light bulb (gas-discharge headlight) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .123
2.14 Replacing turn signal indicator bulb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .123
2.15 Removing and installing headlight range control motor . . . . . . . . . . . . . . . . . . . . . . . . . . . .124
2.16 Removing and installing gas-discharge lamp starter unit -N195 . . . . . . . . . . . . . . . . . . . . . .124
2.17 Installing repair set for headlight housing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .126
2.18 Resetting headlights for driving on left/ right . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .126
3 Servicing fog lights - up to Model Year 2000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .127
3.1 Servicing fog lights - up to Model Year 2000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .127
3.2 Removing and installing fog lights (halogen headlights) . . . . . . . . . . . . . . . . . . . . . . . . . . . .127
3.3 Replacing fog light bulbs (halogen headlights) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .127
3.4 Adjusting fog lights (halogen headlights) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .128
3.5 Removing and installing fog lights (gas-discharge headlights) . . . . . . . . . . . . . . . . . . . . . .128
3.6 Replacing fog light bulbs (gas-discharge headlights) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .129
3.7 Adjusting fog lights (gas-discharge headlights) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .130
4 Servicing fog lights - vehicles as of Model Year 2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .130
4.1 Servicing fog lights - vehicles as of Model Year 2001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .130
4.2 Removing and installing fog lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .131
4.3 Replacing fog light bulbs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .132
4.4 Adjusting fog lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .133
5 Side-mounted turn signal indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .134
5.1 Side-mounted turn signal indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .134
5.2 Removing and installing side-mounted turn signal indicator . . . . . . . . . . . . . . . . . . . . . . . .134
6 Servicing rear lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .135
6.1 Servicing rear lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .135
6.2 Exploded view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .135
6.3 Removing and installing rear light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .136
6.4 Replacing bulbs for rear light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .137
7 Servicing high-level brake light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .137
7.1 Servicing high-level brake light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .137
7.2 Removing and installing high-level brake light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .138
8 Servicing number plate light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .138
8.1 Servicing number plate light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .138
8.2 Removing and installing number plate light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .139
9 Steering column switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .140
9.1 Steering column switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .140
9.2 Safety precautions when working on airbag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .140
9.3 Removing and installing airbag unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .140
9.4 Removing and installing steering column switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .140
9.5 Terminal assignment at steering column switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .143
10 Servicing lock cylinder and ignition/starter switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .146
10.1 Servicing lock cylinder and ignition/starter switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .146
10.2 Removing and installing lock cylinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .146
10.3 Removing and installing ignition/starter switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .148
10.4 Connection assignment at ignition/starter switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .148
11 Servicing parking aid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .149
11.1 Servicing parking aid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .149
11.2 Exploded view of parking aid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .150
11.3 Removing and installing parking aid control unit -J446 . . . . . . . . . . . . . . . . . . . . . . . . . . . .150
11.4 Removing and installing rear parking aid warning buzzer -H15 . . . . . . . . . . . . . . . . . . . . . .151
11.5 Removing and installing rear parking aid sender . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .152
Audi A3 1997 ➤
Electrical system - Edition 10.2003
Contents iii

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
12 Servicing automatic headlight range control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .152
12.1 Servicing automatic headlight range control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .152
12.2 Exploded view of automatic headlight range control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .153
12.3 Removing and installing headlight range control unit -J431 - 3-door model . . . . . . . . . . . .154
12.4 Removing and installing headlight range control unit -J431 - 5-door model . . . . . . . . . . . .155
13 Servicing ultrasonic interior monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .156
13.1 Servicing ultrasonic interior monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .156
13.2 Removing and installing ultrasonic sensors for interior monitor . . . . . . . . . . . . . . . . . . . . . .156
13.3 Removing and installing interior monitor control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .157
96 - Lights, Lamps, Switches - interior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .159
1 Servicing switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .159
1.1 Servicing switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .159
1.2 Removing and installing switches in centre console - up to Model Year 2000 . . . . . . . . . . . .159
1.3 Removing and installing switches in centre console - as of Model Year 2001 . . . . . . . . . . . .160
1.4 Removing and installing front seat heating switch - up to Model Year 2000 . . . . . . . . . . . .161
1.5 Removing and installing front seat heating switch - as of Model Year 2001 . . . . . . . . . . . .161
1.6 Removing and installing light switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .162
1.7 Removing and installing adjuster for manual headlight range control . . . . . . . . . . . . . . . . . .163
1.8 Removing and installing switch for glove box light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .163
1.9 Removing and installing function selection switch II -E272 . . . . . . . . . . . . . . . . . . . . . . . . . .164
1.10 Removing and installing mirror adjustment switch - 3-door model . . . . . . . . . . . . . . . . . . . .165
1.11 Removing and installing mirror adjustment switch - 5-door model . . . . . . . . . . . . . . . . . . . .166
1.12 Removing and installing window lifter switch - 3-door model . . . . . . . . . . . . . . . . . . . . . . . .167
1.13 Removing and installing driver's window lifter switch - 5-door model . . . . . . . . . . . . . . . . . .167
1.14 Removing and installing front passenger's window lifter switch - 5-door model . . . . . . . . . .168
1.15 Removing and installing rear door window lifter switch . . . . . . . . . . . . . . . . . . . . . . . . . . . .169
1.16 Removing and installing sun roof switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .170
1.17 Removing and installing door contact switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .170
1.18 Removing and installing front central locking switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .170
1.19 Removing and installing button for interior monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .171
1.20 Removing and installing tailgate/boot lid contact switch - up to Model Year 2000 . . . . . . . .171
1.21 Removing and installing tailgate/boot lid contact switch - as of Model Year 2001 . . . . . . . .172
2 Servicing immobilizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .172
2.1 Servicing immobilizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .172
2.2 Defective transponder and/or loss of key . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .172
2.3 Replacing reader coil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .173
2.4 Procedure for replacing lock set or dash panel insert . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .173
2.5 System test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .174
3 Servicing interior lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .174
3.1 Servicing interior lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .174
3.2 Removing and installing front interior light/reading light - up to Model Year 1999 . . . . . . . .175
3.3 Replacing bulbs for front interior light/reading light - up to Model Year 1999 . . . . . . . . . . . .175
3.4 Removing and installing front interior light/reading light - as of Model Year 2000 . . . . . . . .176
3.5 Replacing bulbs for front interior light - as of Model Year 2000 . . . . . . . . . . . . . . . . . . . . . .178
3.6 Replacing bulbs for front reading light - as of Model Year 2000 . . . . . . . . . . . . . . . . . . . . . .179
3.7 Removing and installing rear interior light - up to Model Year 1999 . . . . . . . . . . . . . . . . . . . .180
3.8 Replacing bulb for rear interior light - up to Model Year 1999 . . . . . . . . . . . . . . . . . . . . . . . .181
3.9 Removing and installing rear interior light/reading light - as of Model Year 2000 . . . . . . . .181
3.10 Replacing bulb for rear interior light/reading light - as of Model Year 2000 . . . . . . . . . . . . . .182
3.11 Removing and installing luggage compartment lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .182
3.12 Removing and installing glove box light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .183
3.13 Removing and installing make-up mirror light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .183
3.14 Removing and installing door safety light and entry light . . . . . . . . . . . . . . . . . . . . . . . . . . . .184
4 Servicing lock cylinder heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .185
4.1 Servicing lock cylinder heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .185
Audi A3 1997 ➤
Electrical system - Edition 10.2003
iv Contents

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with respect to the correctness of information in this document. Copyright by AUDI AG.
4.2 Removing and installing lock cylinder heater control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . .185
5 Servicing horns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .186
5.1 Servicing horns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .186
5.2 Removing and installing horn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .186
6 Servicing connection socket for towing hitch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .187
6.1 Servicing connection socket for towing hitch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .187
6.2 Removing and installing connection socket for towing hitch . . . . . . . . . . . . . . . . . . . . . . . .187
6.3 Terminal assignment at connection socket for towing hitch . . . . . . . . . . . . . . . . . . . . . . . . . .188
97 - Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .189
1 Relay carriers, fuse carriers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .189
1.1 Relay carriers, fuse carriers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .189
1.2 Removing and installing fuse box for main fuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .189
1.3 Removing and installing fuse box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .190
1.4 Removing and installing central electrics and 13-position relay carrier . . . . . . . . . . . . . . . .192
1.5 Left connector point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .193
1.6 Right connector point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .194
1.7 Relay carrier at bulkhead on left . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .194
2 Wiring harness and connector repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .195
2.1 Wiring harness and connector repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .195
2.2 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .195
2.3 Repairing 0.22 mm2/ 0.35 mm2 wire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .196
2.4 Safety precautions for wiring harness and connector repair . . . . . . . . . . . . . . . . . . . . . . . .197
2.5 Replacing aerial wires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .197
Audi A3 1997 ➤
Electrical system - Edition 10.2003
Contents v

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Audi A3 1997 ➤
Electrical system - Edition 10.2003
vi Contents

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with respect to the correctness of information in this document. Copyright by AUDI AG.
27 - Starter, Current supply
1 - Battery
1.1 - Battery
The battery is one of the most important electrical components in the vehicle. Its proper functioning is a major
factor in ensuring customer satisfaction. To guarantee a long service life, the battery must be checked, serviced
and maintained as described in this manual.
In addition to its starting function, the battery acts as back-up and supplies power for the entire electrical system.
Hazard warning information and safety regulations relating to lead-acid batteries
- -> Pay attention to information given on battery, in electrical system workshop manual and in owner's
manual.
2 - Danger of acid burns:
Electrolyte is highly corrosive; protective gloves and eye protection are therefore always to be worn.
Never tilt battery, as electrolyte may escape from vents.
3 - Fire, sparks, naked flames and smoking prohibited:
Take care to avoid sparks when handling cables and electrical equipment.
Take care to avoid short circuits.
4 - Wear eye protection.
5 - Keep electrolyte and batteries out of children's reach.
6 - Disposal:
Old batteries are to be taken to disposal site.
7 - Old batteries are never to be disposed of with domestic refuse.
8 - Danger of explosion:
Battery charging produces a highly explosive gas mixture.
1.2 - Notes on battery handling
Audi A3 1997 ➤
Electrical system - Edition 10.2003
1.1 - Battery 1

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with respect to the correctness of information in this document. Copyright by AUDI AG.
Notes:
◆ Battery posts are no longer to be greased.
◆ Battery terminals are only to be connected by hand without applying force so as not to damage the battery
casing.
◆ -> Tightening torque for battery terminals: 6 Nm -arrow 1-
◆ Tightening torque of additional terminals at battery terminals: 6 Nm -arrow 2-
1.3 - Removing battery - Audi A3 up to Model Year 2000
Attention:
On vehicles fitted with telematics system, activate telematics control-unit service mode before disconnecting
battery.=>Radio, Telephone, Navigation; Repair Group 91
- Heed (if necessary obtain) code for vehicles with encoded radio/radio navigation system (RNS).
- Switch off ignition.
- -> If fitted, disconnect air intake hose for secondary air pump -1- from air cleaner housing.
- If fitted, screw out bolt -7-.
- Detach air hose -2- at air-mass meter.
- Unplug connector -3- at air-mass meter.
- Screw out bolts -5- and -6-.
- Take out air cleaner housing and detach breather hose -4- at rear if fitted.
- -> If fitted, open upper protective cover of battery -A- (velcro fastener).
- Press release tabs -arrows- and open lid -B- of main fuse box.
Audi A3 1997 ➤
Electrical system - Edition 10.2003
2 27 - Starter, Current supply

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with respect to the correctness of information in this document. Copyright by AUDI AG.
- -> Unfasten nut -3- several turns and disconnect pole shoe of earth wire from battery post.
- Unscrew nut -1- and detach busbar for main fuse box at pole shoe of positive wire.
- Unfasten nut -2- several turns and disconnect pole shoe of positive wire from battery post.
- -> Release retainer for main fuse box. To do so, press down front edge of retainer -arrow 1- and at the same
time detach retainer from battery in direction of travel -arrow 2-.
- Fold back main fuse box and lift off protective cover for battery.
- -> Screw out hexagon bolt -1- at battery bracket -2-.
- Pull battery out of fastening strip of battery bracket.
- Lift battery out of engine compartment.
- Install battery => Page 7 .
Audi A3 1997 ➤
Electrical system - Edition 10.2003
1.3 - Removing battery - Audi A3 up to Model Year 2000 3

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permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
1.4 - Removing battery - Audi A3 as of Model Year 2001
Attention:
On vehicles fitted with telematics system, activate telematics control-unit service mode before disconnecting
battery.=>Radio, Telephone, Navigation; Repair Group 91
- Heed (if necessary obtain) code for vehicles with encoded radio/radio navigation system (RNS).
- Switch off ignition.
- -> Remove cover -1- over battery. To do so, press both release tabs
-arrow-.
- -> Unfasten nut -2- several turns and disconnect pole shoe of earth wire from battery post.
- Unfasten nut -1- several turns and disconnect pole shoe of positive wire from battery post.
- Press release tabs -arrows- and fold back main fuse box.
Audi A3 1997 ➤
Electrical system - Edition 10.2003
4 27 - Starter, Current supply

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with respect to the correctness of information in this document. Copyright by AUDI AG.
- -> Screw out hexagon bolt -1- at battery bracket -2-.
- Pull battery out of fastening strip of battery bracket.
- Lift battery out of engine compartment.
- Install battery => Page 7 .
1.5 - Removing battery - Audi S3
Removing
Attention:
On vehicles fitted with telematics system, activate telematics control-unit service mode before disconnecting
battery.=>Radio, Telephone, Navigation; Repair Group 91
- Heed (if necessary obtain) code for vehicles with encoded radio/radio navigation system (RNS).
- Switch off ignition.
- -> If fitted, remove front left cover -arrows-.
Audi A3 1997 ➤
Electrical system - Edition 10.2003
1.4 - Removing battery - Audi A3 as of Model Year 2001 5

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with respect to the correctness of information in this document. Copyright by AUDI AG.
- -> If fitted, disconnect air intake hose for secondary air pump -1- from air cleaner housing.
- Detach air hose at air-mass meter -2-.
- Unplug connector for air-mass meter -3-.
- Screw out bolts -4- and -5-.
- Take out air cleaner housing.
- -> If fitted, open upper protective cover of battery -A- (velcro fastener).
- Press release tabs -arrows- and open lid -B- of main fuse box.
- -> Unfasten nut -3- several turns and disconnect pole shoe of earth wire from battery post.
- Unscrew nut -1- and detach busbar for main fuse box at pole shoe of positive wire.
- Unfasten nut -2- several turns and disconnect pole shoe of positive wire from battery post.
- -> Release retainer for main fuse box. To do so, press down front edge of retainer -arrow 1- and at the same
time detach retainer from battery in direction of travel -arrow 2-.
- Fold back main fuse box and lift off protective cover for battery.
Audi A3 1997 ➤
Electrical system - Edition 10.2003
6 27 - Starter, Current supply

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- -> Screw out hexagon bolt -1- at battery bracket -2-.
- Pull battery out of fastening strip of battery bracket.
- Lift battery out of engine compartment.
- Install battery => Page 7 .
1.6 - Installing battery
Note:
Batteries from the Audi parts range feature a base strip adapter for matching to different fastening strips.
When and how the base strip adapter is to be used is described in the battery operating instructions.
- -> Insert battery in battery carrier such that lug of battery carrier at rear -arrow- engages in recess in battery
base strip -1-.
- It should no longer be possible to move battery
- -> Battery has been properly inserted if centre recess in battery base strip coincides with tapped hole in
battery carrier -arrows-.
Audi A3 1997 ➤
Electrical system - Edition 10.2003
1.5 - Removing battery - Audi S3 7

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with respect to the correctness of information in this document. Copyright by AUDI AG.
Perform further installation in reverse order, paying attention to the following:
- Pay attention to notes on battery central gas venting system
=>Page 8 .
-> Connect up battery in the following sequence with ignition and electr. loads switched off:
- Attach pole shoe of positive wire by hand to battery positive terminal "+" and tighten nut -2- to 6 Nm.
- If applicable, screw busbar -1- for main fuse box to pole shoe of positive wire (6 Nm).
- Finally attach pole shoe of earth wire by hand to battery negative terminal "-" and tighten nut -3- to 6 Nm.
- Check tightness of battery following installation => Page 9 .
Notes:
◆ On re-connecting battery, remember to activate vehicle equipment (radio/radio navigation system, clock,
electric window lifters) in line with owner's manual.
◆ Deactivate telematics control-unit service mode.
=> Radio, Telephone, Navigation; Repair Group 91
◆ For further operations after re-connecting power supply, refer to
=> Injection and Ignition System; Repair Group 24
Tightening torques
Component Nm
Bolt to bracket 20
Battery terminal to battery post 6
Additional terminal to battery terminal 6
Batteries with central gas venting system
Attention:
Batteries of latest design with central gas venting system are always to be fitted.
Always use genuine battery caps. The caps must be fitted with an O-ring seal.
There are two types of battery with central gas venting system:
◆ Batteries with hose/connection at central gas venting system
◆ Batteries with no hose/connection at central gas venting system
Notes:
◆ The latest generation of batteries features a central gas venting system and a fine-mesh flame trap.
Function: The gas produced on charging escapes centrally through a hole in the top cover. The fine-mesh
flame trap which prevents ignition of the flammable gas in the battery is also located here.
Audi A3 1997 ➤
Electrical system - Edition 10.2003
8 27 - Starter, Current supply

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permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
The fine-mesh flame trap consists of a small round fibre-glass mat with a diameter of approx. 15 mm and a
thickness of 2 mm. It operates in a manner similar to a valve, i.e. it allows the gas produced by battery
gassing to escape.
◆ Battery posts are no longer to be greased.
◆ Battery terminals are only to be connected by hand so as not to damage the battery casing.
Notes on operation of central gas venting system:
◆ On batteries with central gas venting hose/pipe, make sure that hose does not become disconnected as
otherwise the battery will not be properly vented.
◆ -> On batteries with no central gas venting hose/pipe, it is important to ensure that opening in top cover -
arrow- is not clogged.
Checking firm attachment of battery
Possible dangers if battery is not firmly in position:
- Shorter service life due to vibration damage
- Damage to battery plates if battery not properly attached
- Damage to battery casing caused by bracket (possible electrolyte leakage, high subsequent costs)
- Reduced crash safety
- To ensure that battery does not leak, only fit genuine battery caps.
- In the event of loss or damage, make exclusive use of genuine caps of the same type.
- The caps must be provided with an O-ring.
1.7 - Battery with magic eye
-> Distinguishing features
◆ Such batteries have a magic eye.
◆ This magic eye -arrow- provides information on the electrolyte level and charge of the battery to be tested.
◆ There are three different colour indicators:
- Green ⇒Battery adequately charged
- Black ⇒ Not or inadequately charged
Audi A3 1997 ➤
Electrical system - Edition 10.2003
1.6 - Installing battery 9

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permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
- Colourless or yellow ⇒Critical electrolyte level reached; topping up with distilled water essential
Note:
If a battery is more than 5 years old and the indicator of the magic eye is colourless, the battery is to be replaced
with a new one.
Test sequence
Notes:
◆ Air bubbles may form under the magic eye, particularly if a battery has been re-charged, i.e. even if the
battery has been charged whilst driving. These air bubbles falsify the colour indicator of the magic eye.
◆ If batteries are fitted with caps for production reasons, these are covered with plastic sheeting.
- Before performing visual inspection, tap gently and carefully on magic eye with the handle of a screwdriver.
- This disperses the air bubbles
- Observe colour of "magic eye" indicator.
1.8 - Visual inspection
Attention:
The battery caps must always be firmly screwed on for charging, voltage measurement and load measurement.
Visually inspect battery before performing measurements, e.g. no-load voltage, specific gravity of electrolyte
or battery load test.
Such inspection is designed to establish:
◆ Whether battery casing is damaged.
A damaged casing can result in electrolyte leakage.
◆ Whether battery posts (battery connections) are damaged.
Proper contact of connections is not ensured if battery posts are damaged. This may then result in cable
burn-out and electrical system malfunctions.
1.9 - Checking electrolyte level
Attention:
Always heed accident prevention regulations when handling electrolyte.
Always wear suitable protective clothing.
Only use torch to illuminate inside of battery casing.
Never illuminate inside of battery casing with a naked flame.
Keep naked flames and burning cigarettes away from batteries.
When disposing of batteries, always pay attention to the appropriate regulations for batteries and sulphuric
acid.
To ensure that the various battery cover systems do not leak, only screw genuine battery caps into battery
openings. In the event of loss or damage, make exclusive use of genuine caps of the same type.
The caps must be fitted with an O-ring seal.
Audi A3 1997 ➤
Electrical system - Edition 10.2003
10 27 - Starter, Current supply

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
Special tools and workshop equipment required
◆ Battery filler VAS 5045
◆ Commercially available hydrometer
Notes:
◆ The correct electrolyte level is an important factor in ensuring a long battery service life.
◆ On batteries with visiblemin. and max. marks, electrolyte level can be checked simply by visually inspecting
outside of battery.
◆ Electrolyte level must be above min. mark, but must not exceed max. mark.
◆ On batteries on which the outermin. and max. marks are difficult to see or proper checking of the electrolyte
level cannot be guaranteed on account of the opaque nature of the battery casing, the caps have to be
unscrewed. The electrolyte level can then be checked by way of a visual inspection of the inside of the
battery.
◆ The electrolyte level must coincide with the internal level mark (plastic web). This corresponds to the outer
max. mark.
◆ -> On batteries with a magic eye -arrow-, the electrolyte level can be established from the colour indicator.
◆ Test sequence => Page 9
Electrolyte level too low
Note:
If the electrolyte level is too low, drying-out of the cell plates will reduce the capacity (power) of the battery. If
the cell plates are not surrounded by electrolyte, the plates, plate links and cell connectors will become corroded.
The function of the battery is then not guaranteed and it becomes unusable.
- -> If the electrolyte level is too low, use battery filler bottle VAS 5045 to top up distilled water as far as max.
mark.
Notes:
◆ The filler neck of the filler bottle VAS 5045 is designed to prevent over-filling of the battery cell and electrolyte
leakage. The flow of distilled water into the battery cell is interrupted on reaching the max. level.
Audi A3 1997 ➤
Electrical system - Edition 10.2003
1.9 - Checking electrolyte level 11

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
◆ Always use distilled water for topping up to prevent electrolyte contamination which results in increased self-
discharge.
- Screw battery cell caps back in again => Page 8 (batteries with central gas venting system).
Electrolyte level too high
Note:
If the electrolyte level is too high, escaping electrolyte (mixture of sulphuric acid and water) will cause damage
outside the battery, e.g. on components in the engine compartment.
- -> If electrolyte level is too high (overfilled), i.e. if level is above inner electrolyte mark (plastic web) or above
outer max. mark, excess electrolyte must always be drawn off using a commercially available hydrometer.
- Use hydrometer to draw off sulphuric acid until electrolyte level reaches plastic web/max. mark.
- Screw battery cell caps back in again => Page 8 (batteries with central gas venting system).
Audi A3 1997 ➤
Electrical system - Edition 10.2003
12 27 - Starter, Current supply