1998-2002 Audi A8/S8 Fuse Box Diagram [D2/4D]

The fuse box diagram is a helpful tool for troubleshooting electrical problems in your Audi A8/S8 D2/4D from 1998 to 2002. It shows the location of each fuse in the fuse box, as well as the amperage rating and function of each fuse.

By understanding the fuse box diagram, you can quickly and easily identify which fuse may be blown when you are having an electrical problem. This can save you time and money by preventing you from having to take your car to a mechanic for every small electrical problem.

There are two fuse boxes in the Audi A8/S8 D2/4D from 1998 to 2002. The first fuse box is located under the left side of the dashboard. The second fuse box is located in the luggage compartment.

Passenger Compartment

Fuse NumberFuse AmpsDescription
ST1Fuse carrier 1, black
ST2Fuse carrier 2, red
ST3Fuse carrier 3, yellow
ST4Fuse carrier 4, blue
ST5Fuse carrier 5, brown
6Secondary air pump fuse
7Spare fuses
8Radiator fan fuse
ST1-15ALeft side light/parking light, left tail light
ST1-25ARight side light/parking light, right tail light
ST1-315ADipped beam headlight, right
ST1-415ADipped beam headlight, left, headlight range control
ST1-510AMain beam headlight, left
ST1-610AMain beam headlight, right, main beam warning lamp
ST1-715AHazard warning lights
ST1-815ADual tone horn
ST1-910ADiagnostic socket (30a)
ST1-1025AWindscreen wiper system, automatic intermittent wash/ wipe relay
ST2-110AMirror heating
ST2-210AHeated steering wheel
ST2-35ADisplay and switch illumination, storage compartment, cup holder, number plate light
ST2-45ARadiator fan relay, air quality sensor
ST2-515AFront fog lights, rear fog light, fog lights/rear fog light control unit
ST2-630AHeated rear window, air conditioner
ST2-75ASteering angle sensor for ESP
ST2-810AHazard warning lights, terminal 75
ST2-910ABrake lights
ST2-105AHeated washer jets
ST3-115ABulb monitoring, on-board computer, dash panel insert, parking aid, diagnostic socket (15a), tyre pressure monitor, multi-function steering wheel, headlight range control
ST3-25ATelephone, telematics, navigation system with screen
ST3-315ACigarette lighter, front
ST3-410AAir conditioner, parking aid, auxiliary heating radio wave receiver, multi-function steering wheel, dash panel insert, solar cell isolation relay, tyre pressure monitor
ST3-510AAir conditioner
ST3-610ACruise control system, reversing lights
ST3-715AAir conditioner, coolant pump
ST3-810AAir conditioner compressor, magnetic coupling
ST3-95AMulti-function steering wheel
ST3-1020AAdditional heater control unit, auxiliary heater
ST4-120AFuel pump
ST4-230AV8, V12: Ignition coils
V6: Output stage
ST4-320A/10ALambda probe heating
V8 TDI: Fuel pump
ST4-410A/15AV8 TDI: Fuel cooling pump
V6: Brake servo relay
ST4-55ANavigation system NS Low
ST4-610ANavigation system NS Low, chip card reader unit
ST4-85AOil level thermo sender
ST4-925AControl unit for ABS (ESP), terminal 30
ST4-1010AControl unit for ABS, terminal 15
ST5-110AIlluminated vanity mirrors, central locking, indicator lights for anti-theft alarm system operation, interior lights, reading lamps
ST5-210AMirror adjustment, mirror retraction, control units for electric windows , toll pass, rear head restraint adjustment, potentiometer for seat heating, seat adjustment memory
ST5-310AEntry and footwell lights, ultra-sonic sensor control unit, internal central locking switch, mirror and seat adjustment with memory function, luggage compartment release
ST5-410ACentral locking, automatic anti-dazzle interior mirror, rear roller blind, reading lamp relay
ST5-515ACentral locking
ST5-620ASliding/tilting sunroof
ST5-715ARear cigarette lighter, heated lock cylinders, adjustable front passenger’s seat
ST5-8Not used
ST5-920ASteering column and belt height adjustment
ST5-1020AHeated front seats, rear roller blind

Relay Panels

Relay NumberDescription
1Starter inhibitor relay-automatic gearbox
Bridge connection on models with manual gearbox
2Adjustable front passenger’s seat relay
3Seat adjustment thermo-fuse 2
4Seat adjustment thermo-fuse 1
5Daytime driving light switch-on relay
6Fuel cooling relay (TDI)
7Hot air blower single fuse

Micro-central electrics in electronics box (footwell)

Relay NumberDescription
1X Contact relief relay
2X contact relief relay
4Relay for glow plugs (V6 TDI)
Fuel pump relay (V6, V8, V12)
Voltage supply relay (V8 TDI)
5Electric fuel pump 2 relay (V8 TDI)
Radiator fan relay (countries with hot climate, V12)
Brake servo relay (V6)
6Daytime driving light change-over relay

Relay carrier in electronics box (footwell)

Relay NumberDescription
1Bulb monitoring device
2TDI engine: Fuel pump relay
V8, V12 engine: Motronic current supply relay
3Fog lights/rear fog light control unit
4Automatic intermittent wash/wipe relay
5Entry and footwell lighting relay
6Bulb monitoring device
7Coolant shut-off valve relay
8Fog lights/rear fog light control unit
9Automatic intermittent wash/wipe relay
10Exterior mirror fold system control unit
11Reading lamp relay
12Servotronic control unit
13Solar cell isolation relay
14Magnetic coupling relay
15Exterior mirror fold system control unit

Relay carrier under the shelf on the driver’s side

Relay NumberDescription
1Relay for ABS solenoid valves
2ABS return flow pump relay
3Multi-function steering wheel control unit
4Multi-function steering wheel control unit
6Hazard warning light relay
Models with trailer coupling: Hazard warning light relay, trailer operation
7Front electric window thermo-fuse
8Rear electric window thermo-fuse

Luggage Compartment Fuse Box

Fuse NumberDescription
1Terminal 30 junction box
2ABS hydraulic pump fuse
3Heated seats single fuse
4Terminal 30 fuse-trailer operation
6Radio fuse
Navigation fuse
7ABS valves fuse
9Telephone fuse
14Seat adjustment fuse
Models without rear seat adjustment: Rear head restraint adjustment fuse

Engine Compartment Electronics Box

V6, V8 & V12 Petrol engines

Fuse/Relay NumberDescription
1V12: Engine control unit fuse
2aV12: Secondary air pump relay 1
2bV12: Secondary air pump relay 1
V6, V8: Automatic gearbox control unit fuse
3V12: Injector fuse
4V6, V8: Secondary air pump relay
V12: Control element fuse
V12: Coolant pump fuse
5V12: Automatic gearbox control unit fuse
6V6, V8: Injector fuse
V12: Continued coolant circulation relay
7V6, V8: Control element fuse
V12: Continued coolant circulation relay
8V12: Control element fuse 2
9V8: Engine control unit fuse
V12: Secondary air pump relay 2
10V12: Secondary air pump relay 2

V6 diesel engines (TDI)

Relay NumberDescription
1Fuse 1 for glow plugs-engine
2aAlternator cut-in relay
2bAlternator cut-in relay
4Automatic gearbox control unit fuse
5Fuse 2 for glow plugs-engine
6Diesel direct injection system relay
7Diesel direct injection system relay
9Air mass meter fuse
10Engine control unit fuse

V8 Diesel engines (TDI)

Fuse NumberDescription
1Regulating valve fuse
2Glow plug relay 2
3Charge air cooling pump relay
4Automatic gearbox control unit fuse
5Coolant pump fuse
6Alternator cut-in relay
7Engine control unit fuse
8Relay for glow plugs
9Fuse 2 for glow plugs-engine
10Fuse 1 for glow plugs-engine
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Tom Smith is a passionate car mechanic and automotive enthusiast, specializing in the intricate world of car fuse boxes. With years of hands-on experience under the hood, he has earned a reputation as a reliable expert in his field. As the founder and content creator of the popular blog website 'carsfuse.com,' Tom has dedicated himself to sharing his extensive knowledge of car fuse boxes and electrical systems with the world.

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