1998 – 2002 Audi (A8 & S8) Fuse Box Diagrams & Location User Guide
This blog covers the fuse box diagrams and locations for the 1998 to 2002 Audi A8 and S8. It provides easy-to-follow information to help you find and manage your vehicle’s fuse boxes, making fuse replacement and electrical repairs hassle-free.
Location of fuse and relay boxes
- Electronics box in plenum chamber
- Airbag control unit
- Diagnostic connector in centre console, under ashtray
- Relay and fuse carrier, luggage compartment, right
- Battery / additional battery
- Anti-theft alarm system horn
- Bracket for control units
- Mirror memory control unit, B pillar, driver’s side
- Steering column/belt height adjustment control unit, under carpet, driver’s seat (rear section)
- Heated lock cylinder control unit
- Relay under shelf on driver’s side (auxiliary relay carrier at wheelhouse, left)
- ABS control unit and radiator fan 3rd speed relay, under shelf on driver’s side
- Electronics box, front passenger’s footwell
- Fuse box, right A-pillar, behind trim in front passenger’s footwell
Passenger Compartment Fuse Box
1998 to 2002 Audi (A8 & S8)
Fuse Box Location
The fuse box is located in the front passenger’s footwell.
Fuse Box Diagram
| No | Amps | Description |
|---|---|---|
| ST1 | Fuse carrier 1, black | |
| ST2 | Fuse carrier 2, red | |
| ST3 | Fuse carrier 3, yellow | |
| ST4 | Fuse carrier 4, blue | |
| ST5 | Fuse carrier 5, brown | |
| 6 | Secondary air pump fuse | |
| 7 | Spare fuses | |
| 8 | Radiator fan fuse | |
| ST1-1 | 5A | Left side light/parking light, left tail light |
| ST1-2 | 5A | Right side light/parking light, right tail light |
| ST1-3 | 15A | Dipped beam headlight, right |
| ST1-4 | 15A | Dipped beam headlight, left, headlight range control |
| ST1-5 | 10A | Main beam headlight, left |
| ST1-6 | 10A | Main beam headlight, right, main beam warning lamp |
| ST1-7 | 15A | Hazard warning lights |
| ST1-8 | 15A | Dual tone horn |
| ST1-9 | 10A | Diagnostic socket (30a) |
| ST1-10 | 25A | Windscreen wiper system, automatic intermittent wash/ wipe relay |
| ST2-1 | 10A | Mirror heating |
| ST2-2 | 10A | Heated steering wheel |
| ST2-3 | 5A | Display and switch illumination, storage compartment, cup holder, number plate light |
| ST2-4 | 5A | Radiator fan relay, air quality sensor |
| ST2-5 | 15A | Front fog lights, rear fog light, fog lights/rear fog light control unit |
| ST2-6 | 30A | Heated rear window, air conditioner |
| ST2-7 | 5A | Steering angle sensor for ESP |
| ST2-8 | 10A | Hazard warning lights, terminal 75 |
| ST2-9 | 10A | Brake lights |
| ST2-10 | 5A | Heated washer jets |
| ST3-1 | 15A | Bulb monitoring, on-board computer, dash panel insert, parking aid, diagnostic socket (15a), tyre pressure monitor, multi-function steering wheel, headlight range control |
| ST3-2 | 5A | Telephone, telematics, navigation system with screen |
| ST3-3 | 15A | Cigarette lighter, front |
| ST3-4 | 10A | Air conditioner, parking aid, auxiliary heating radio wave receiver, multi-function steering wheel, dash panel insert, solar cell isolation relay, tyre pressure monitor |
| ST3-5 | 10A | Air conditioner |
| ST3-6 | 10A | Cruise control system, reversing lights |
| ST3-7 | 15A | Air conditioner, coolant pump |
| ST3-8 | 10A | Air conditioner compressor, magnetic coupling |
| ST3-9 | 5A | Multi-function steering wheel |
| ST3-10 | 20A | Additional heater control unit, auxiliary heater |
| ST4-1 | 20A | Fuel pump |
| ST4-2 | 30A | V8, V12: Ignition coils V6: Output stage |
| ST4-3 | 20A/10A | Lambda probe heating V8 TDI: Fuel pump |
| ST4-4 | 10A/15A | V8 TDI: Fuel cooling pump V6: Brake servo relay |
| ST4-5 | 5A | Navigation system NS Low |
| ST4-6 | 10A | Navigation system NS Low, chip card reader unit |
| ST4-7 | – | – |
| ST4-8 | 5A | Oil level thermo sender |
| ST4-9 | 25A | Control unit for ABS (ESP), terminal 30 |
| ST4-10 | 10A | Control unit for ABS, terminal 15 |
| ST5-1 | 10A | Illuminated vanity mirrors, central locking, indicator lights for anti-theft alarm system operation, interior lights, reading lamps |
| ST5-2 | 10A | Mirror adjustment, mirror retraction, control units for electric windows , toll pass, rear head restraint adjustment, potentiometer for seat heating, seat adjustment memory |
| ST5-3 | 10A | Entry and footwell lights, ultra-sonic sensor control unit, internal central locking switch, mirror and seat adjustment with memory function, luggage compartment release |
| ST5-4 | 10A | Central locking, automatic anti-dazzle interior mirror, rear roller blind, reading lamp relay |
| ST5-5 | 15A | Central locking |
| ST5-6 | 20A | Sliding/tilting sunroof |
| ST5-7 | 15A | Rear cigarette lighter, heated lock cylinders, adjustable front passenger’s seat |
| ST5-8 | Not used | |
| ST5-9 | 20A | Steering column and belt height adjustment |
| ST5-10 | 20A | Heated front seats, rear roller blind |
Relay Panels
The relay panels are located in electronics box, front passenger’s footwell.
Auxiliary fuse and relay carrier in electronics box (footwell)
| No | Description |
|---|---|
| 1 | Starter inhibitor relay-automatic gearbox Bridge connection on models with manual gearbox |
| 2 | Adjustable front passenger’s seat relay |
| 3 | Seat adjustment thermo-fuse 2 |
| 4 | Seat adjustment thermo-fuse 1 |
| 5 | Daytime driving light switch-on relay |
| 6 | Fuel cooling relay (TDI) |
| 7 | Hot air blower single fuse |
Micro-central electrics in electronics box (footwell)
| No | Description |
|---|---|
| 1 | Dual tone horn relay |
| 2 | X contact relief relay |
| 4 | Relay for glow plugs (V6 TDI) Fuel pump relay (V6, V8, V12) Voltage supply relay (V8 TDI) |
| 5 | Electric fuel pump 2 relay (V8 TDI) Radiator fan relay (countries with hot climate, V12) Brake servo relay (V6) |
| 6 | Daytime driving light change-over relay |
Relay carrier in electronics box (footwell)
| No | Description |
|---|---|
| 1 | Bulb monitoring device |
| 2 | TDI engine: Fuel pump relay V8, V12 engine: Motronic current supply relay |
| 3 | Fog lights/rear fog light control unit |
| 4 | Automatic intermittent wash/wipe relay |
| 5 | Entry and footwell lighting relay |
| 6 | Bulb monitoring device |
| 7 | Coolant shut-off valve relay |
| 8 | Fog lights/rear fog light control unit |
| 9 | Automatic intermittent wash/wipe relay |
| 10 | Exterior mirror fold system control unit |
| 11 | Reading lamp relay |
| 12 | Servotronic control unit |
| 13 | Solar cell isolation relay |
| 14 | Magnetic coupling relay |
| 15 | Exterior mirror fold system control unit |
Relay carrier under shelf on driver’s side
| No | Description |
|---|---|
| 1 | Relay for ABS solenoid valves |
| 2 | ABS return flow pump relay |
| 3 | Multi-function steering wheel control unit |
| 4 | Multi-function steering wheel control unit |
| 6 | Hazard warning light relay Models with trailer coupling: Hazard warning light relay, trailer operation |
| 7 | Front electric window thermo-fuse |
| 8 | Rear electric window thermo-fuse |
Auxiliary relays (for radiator fan)
The first speed, second speed and third speed radiator fan relays are located-in direction of travel-in front of the ABS / ESP control unit under shelf on driver’s side.
Luggage Compartment Fuse Box
1998 to 2002 Audi (A8 & S8)
It is on the right side.
| No | Description |
|---|---|
| 1 | Terminal 30 junction box |
| 2 | ABS hydraulic pump fuse |
| 3 | Heated seats single fuse |
| 4 | Terminal 30 fuse-trailer operation |
| 6 | Radio fuse Navigation fuse |
| 7 | ABS valves fuse |
| 9 | Telephone fuse |
| 14 | Seat adjustment fuse Models without rear seat adjustment: Rear head restraint adjustment fuse |
Engine Compartment Electronics Box
1998 to 2002 Audi (A8 & S8)
It is on the passenger’s side under a cover.
V6, V8 and V12 petrol engines
| No | Description |
|---|---|
| 1 | V12: Engine control unit fuse |
| 2a | V12: Secondary air pump relay 1 |
| 2b | V12: Secondary air pump relay 1 V6, V8: Automatic gearbox control unit fuse |
| 3 | V12: Injector fuse |
| 4 | V6, V8: Secondary air pump relay V12: Control element fuse V12: Coolant pump fuse |
| 5 | V12: Automatic gearbox control unit fuse |
| 6 | V6, V8: Injector fuse V12: Continued coolant circulation relay |
| 7 | V6, V8: Control element fuse V12: Continued coolant circulation relay |
| 8 | V12: Control element fuse 2 |
| 9 | V8: Engine control unit fuse V12: Secondary air pump relay 2 |
| 10 | V12: Secondary air pump relay 2 |
V6 diesel engines (TDI)
| No | Description |
|---|---|
| 1 | Fuse 1 for glow plugs-engine |
| 2a | Alternator cut-in relay |
| 2b | Alternator cut-in relay |
| 4 | Automatic gearbox control unit fuse |
| 5 | Fuse 2 for glow plugs-engine |
| 6 | Diesel direct injection system relay |
| 7 | Diesel direct injection system relay |
| 9 | Air mass meter fuse |
| 10 | Engine control unit fuse |
V8 diesel engines (TDI)
| No | Description |
|---|---|
| 1 | Regulating valve fuse |
| 2 | Glow plug relay 2 |
| 3 | Charge air cooling pump relay |
| 4 | Automatic gearbox control unit fuse |
| 5 | Coolant pump fuse |
| 6 | Alternator cut-in relay |
| 7 | Engine control unit fuse |
| 8 | Relay for glow plugs |
| 9 | Fuse 2 for glow plugs-engine |
| 10 | Fuse 1 for glow plugs-engine |