Audi A8 (D2) | 1994-2002 | Fuse Box Diagrams and Locations

The first-generation Audi A8 and S8 (chassis codes D2/4D), Audi’s premier luxury sedan and its high-performance variant, was produced in 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001 and 2002. As Audi’s first full-size luxury sedan built with the innovative aluminum-intensive ASF (Audi Space Frame) construction, this generation set new standards in lightweight design, performance, and luxury.

In this article, you will find detailed fuse box diagrams for Audi A8 and S8 models produced between 1994 and 2002. These diagrams provide critical insights into the vehicle’s electrical systems, including the assignment of each fuse (fuse layout) and relay. This knowledge is essential for diagnosing electrical issues, performing maintenance, or completing necessary repairs.

This guide serves as a comprehensive resource for understanding the electrical system of the first-generation Audi A8 and S8, ensuring that owners have the information needed to maintain the reliability, functionality, and performance of these groundbreaking luxury sedans.

What’s Included

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

Fuse Box Location

The fuse box is located in the front passenger’s footwell.

Location of the fuses in the passenger compartment: Audi A8 (1998-2002)

Fuse Box Diagram

Assignment of the fuses in the passenger’s footwell

№	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)

Auxiliary fuse and relay carrier in electronics box: Audi A8 (1998, 1999, 2000, 2001, 2002)

№	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)

Micro-central electrics: Audi A8 (1998, 1999, 2000, 2001, 2002)

№	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)

Relay carrier in electronics box: Audi A8 (1998, 1999, 2000, 2001, 2002)

№	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

№	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.

Auxiliary relays: Audi A8 (1998, 1999, 2000, 2001, 2002)

Luggage Compartment Fuse Box

It is on the right side.

№	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

It is on the passenger’s side under a cover.

Location of the fuses in the engine compartment: Audi A8 (1998-2002)

V6, V8 and V12 petrol engines

Engine Electronics Box (v.1): Audi A8 (1998, 1999, 2000, 2001, 2002)

№	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)

Engine Electronics Box (v.2): Audi A8 (1998, 1999, 2000, 2001, 2002)

№	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)

Engine Electronics Box (v.3): Audi A8 (1998, 1999, 2000, 2001, 2002)

№	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