Audi A4 (B7, 2004 - 2007) fuses and relays

A4 B7 - the third generation of the mid-size car of the German company Audi, model range from 2004 to 2007. It is an updated model B6. In this material, we will analyze in detail the fuse diagrams of the 3rd generation Audi A4 (B7)  2004, 2005, 2006, 2007, 2008, 2009  with gasoline and diesel engines 1.6 8V, 1.8 20V turbo, 1.9 TDI, 2.0 FSI, 2.4 V6 , 2.5TDI V6, 3.0 V6, 4.2 V8.

General view of the car.
Here you will find the locations and photos of the mounting blocks. Separately, we note the fuses responsible for the cigarette lighter and fuel pump.

General arrangement

Location of electronic components.

No. Component
1 Air conditioning control unit - in the heater control panel - functions: Rear window defroster, front seat heaters Steering wheel heater
2 A/C/Heater Fan Control Unit - Fan Unit
3 Aerial Select Control Unit (Sedan with 'Concert II/Symphony II' Audio System) - Rear Dome Panel, Center
4 Antenna Booster (Sedan with 'ChorusII' Audio System) - Rear Dome Panel, Center
7 Collision sensor, driver's side - engine compartment
8 Crash sensor, passenger side - engine compartment
9 Vehicle tilt sensor (anti-theft system) - in the multifunction control unit2
10 Anti-Theft Alarm - Luggage Compartment, Behind Right Trim Panel
11 Volume change sensor (anti-theft system) - front interior lamp
12 Audio output amplifier - luggage compartment, behind right trim panel
13 Additional heater control unit - behind the arch of the left front wheel
14 Accumulator battery
15 Clock synchronization unit (with digital multifunction display) - behind the rear bumper
16 Diagnostic connector (DLC) - under the dashboard, on the driver's side
17 Diagnostic unit - on the dashboard
18 Door Function Control Module, Front Left (Central Locking/Door Mirror/Power Window) - Door
19 Door Function Control Module, Front Right (Central Locking/Door Mirror/Power Window) - Door
20 Door function control unit, rear left (central lock/power window) - door
21 Door function control unit, rear right (central lock/power window) - door
22 Cooling fan motor control unit - on the radiator
23 Fuse/Relay Boxes Behind Dashboard 
27 Fuse/Relay Box 5, Dashboard - Taxi
28 Fuse/Relay Box, 6-Taxi Dashboard
29 Fuse/Relay Box, Engine Compartment - Under ECM/TCM
30 Main fuse (150A) - battery
31 Headlight control unit, left (models with xenon headlights)

In the underhood space

Location of the fuse box in the engine compartment of the car
The block is located on the right side of the engine compartment under the ECM / TCM.

General view (removed for clarity).

Diesel engines
No. Description A
F1 Engine Management System, Stop Lamp Switch (Brake Pedal Position Sensor) 15
F2 glow plugs 60/80
F3 Automatic transmission control system (6-speed automatic transmission / Multitronic) 15
F4 glow plugs 60
1 Fuel pump relay
2 Transmission control relay (Multitronic)
3 Glow plug relay
4 Engine management relay
5 Start Inhibit Switch Relay/Reversing Lamp Relay (Multitronic)
Petrol engines
No. Decryption A
F1 Engine Management System, Stop Lamp Switch (Brake Pedal Position Sensor) 15
F2 Exhaust air pump motor (if equipped) 40
F3 Automatic transmission control system (6-speed automatic transmission / Multitronic) 15
1 Coolant heater relay (V6) (if equipped)
2 Transmission control relay (Multitronic)
3 Exhaust air pump relay
4 Coolant pump motor control unit (AMM/BDV) (if equipped)
5 Start inhibit switch relay (if equipped)

In the passenger compartment

Location of the main fuse box in the passenger compartment
There are four fuse blocks in the cabin space. The main cabin unit is located at the end of the dashboard on the driver's side.

Fuse box

General form

No. A Purpose
1 10 air conditioning
2 5 footwell lights
3 5 Heated windshield washer jets
4 5 cooling fan
5 10 telephone, engine oil level sensor, multifunction switches, heated rear seats, rear window shade, automatic transmission (shift gate)
6 5 air conditioning (air quality assessment sensor), pressure sensor
7 10 Electronic Stability Program (ESP), Brake Switch, Clutch Pedal Sensor, Steering Angle Sensor
8 5 telephone
9 15 brake booster (vacuum pump)
10 5 automatic headlight range adjustment. Adaptive light (turning light) right
11 - empty
12 10 diagnostic socket
13 10 steering column module
14 10 brake lights
15 10 instrument cluster, navigation system
16 5 garage door opener
17 10 parking assistance, ride height control, tire pressure monitoring, rain/light sensor
18 5 Adaptive light (turning light) on the left
19 15 fog light
20 empty
21   is absent
22 15 driver/front passenger door
23 15 rear doors
24 20 comfortable electrical equipment with central control
25 30 heater fan
26 30 rear window heating
27 30 trailer socket (control unit)
28 20 fuel module (fuel pump fuse), auxiliary diesel pump
29 - is absent
30 20 sliding roof panel
31 15 automatic transmission, diagnostic socket, automatically shielded interior mirror
32 20 trailer socket
33 15 audi b7 cigarette lighter fuse
34 - is absent
35 20 socket in trunk
36 30 wiper
37 30 windshield washer pump and headlight cleaners
38 15 Comfort electrical system with central control, trunk release
39 20 radio system
40 25 sound signal
41 30 heater
42 25 electronic stability program (ESP)
43 15 engine management
44 35 seat heating

Additional relay blocks

Location of additional relay and fuse boxes in the passenger compartment
Located behind the front trim on the driver's side. To access, you need to remove the lining of the steering column space.

Relay box #1
No. Purpose A
F1 empty -
F2 Thermal fuse for electric rear window blind 10
F3 empty -
F4  Thermal fuse for the electric drive of the rear windows 30
F5 Power seats (adjustable lumbar support) 10
F6 Thermal fuse for electric front windows 30
F7 Trailer electrical connector 30
1 Fuel pump relay - gasoline (fuel module, fuel pump relay)
2 Power steering (Servotronic) control unit (if equipped)
3 Horn relay (dual tone)
4 Brake Booster Vacuum Pump Relay (If Equipped)
5 empty
6 Ignition Auxiliary Relay
7 empty
8 empty
9 empty
Relay box #2
No. Decryption A
A empty -
B Optional equipment
C empty -
D empty -
E Anti-lock braking system ABS (ABS) 50
F Control unit 1 cooling fan motor 40/60
G Service vehicles 10
H Cooling Fan Motor Control Module 2 - If Equipped
1 empty
2 empty
3 empty
4 Control unit 3 for the taxi-hands-free alarm system
Relay box #3

General form.

No. Purpose A
A Additional heater - 2003 30
C Coolant heater 40
B 60
1 empty
2 Coolant Heater Relay 2 - High Power
3 Coolant Heater Relay 1 - Low Power
Related fuse diagrams
Sedric Ketchum

Where would I look for a, 2006 A4 Quattro 2.0t? It gives you no option. 2005 then skips 2 years to 2007? What's the deal? Is there some secret about the 2006 Audi A4..? Real though these parts are getting pretty expensive. Really could use a lay out, diagram something of that years relay\ fuse box.


All B7 A4 (late 2005 to early 2008) are the same vehicle (same diaphragm)


Thank you for posting this information. I’ve seen other posts on the net regarding relay and fuse diagrams, but this one is much more thorough and descriptive.

Chris Cooper

Currently diagnosing a no A/C/blower fan motor condition. What’s really weird is I have tested every single relay and every single fuse and they all test as functional. At this point, I am checking the actual wire that goes to the blower motor and checking for Continuity. It’s weird because there’s no black burn marks on the wire at the connector or on the wire even tracing serval feet of it there’s nothing showing that it has been damaged.

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