Audi 80/Avant (B4)

since 1991-1995 release

Repair and operation of the car

Audi 80/Avant
+ Technical specification
+ Engines
+ System of production of the fulfilled gases
+ Cooling system
+ Fuel tank and fuel pump
+ Air filter and airintaking channels
+ System of injection
+ Coupling
+ Transmission and transmission
+ Suspension bracket and steering
+ Brake system
+ Anti-blocking system of brakes
+ Wheels and tires
- Body electrical system
   Minus to "weight"
   Orientation in the electrical system
   Plug connections
   Central switchboard
   Additional block of the relay
   Relay and control units
   Unloading relay of contact of X
   Safety locks
   Table of safety locks
   Electric circuits
   + Full electroscheme of the Audi 80 car: 2-liter 4-cylinder engine (66 kW)
   + 2-liter 4-cylinder engine (85 kW)
   + 2,3-liter 5-cylinder engine (98 kW)
   + 2,6-liter 6-cylinder engine (110kvt)
   + Additional equipment
   + Battery
   + Generator
   Check of a condition of a maple or polilinovy belt
   Tension of a maple belt
   Tension of a maple or poliklinovy belt
   The belt torn maple
   Engine overheat because of damage of a maple belt
   Review of maple and poliklinovy belts
   Replacement of a maple belt
   List of malfunctions
   List of malfunctions
+ System of ignition
+ Lighting
+ Signalling devices
+ Devices and auxiliary devices
+ Heating and ventilation
+ body Elements
+ Search of malfunctions
+ Specifications

Central switchboard

The central switchboard is located in the Audi 80 car in a waterproof casing under a windshield. Can be in it to 31 safety locks (one more, if the car with the diesel engine), four reserve safety locks and in total eleven relays. Besides, shtekerny connection for connection of the diagnostic unit is located in the same place.

1 – the relay for fog lights and back marker lights, the bridge if the car is not equipped with fog lights;
2 – the cooling system fan relay (the model which are not equipped with the conditioner), the relay for the second fan of the cooling system;
3 – the control unit of turning on of the fan after termination of work of the engine;

4 – control unit of system of cleaning of headlights;
5 – unloading relay of H-contact.

6 – the fan relay (on models with the manual conditioner), the relay of the second fan of the cooling system (on models with the automatic conditioner and some options of the engine);
7 – relay of a sound signal;
8 – the relay of system of the alarm system (on models from mechanical KP), the bridge on the models which are not equipped with system of the alarm system. On the models equipped with AKP, this place remains empty;

9 – relay of the faltering mode of system of screen wiper/washing of glasses;
10 – relay of the fuel pump;
11 – relay of the first fan of the cooling system.

All wires in Audi 80 are collected in various plaits. All of them come to an end in the so-called central switchboard, a black box located at the left behind in a motor compartment in a waterproof casing. There it is possible to place 21 safety locks, ten additional safety locks, four reserve safety locks and a number of the relay.

Replacement of the central switchboard

If by search of malfunctions it was found out that the eyeliner of cables, the corresponding safety locks or the relay have no damages, also the central switchboard can be a cause of defect. The leaky contacts or refusals connected with temperature can be typical damages. In this case it is necessary to replace the central switchboard.


  1. As a spare detail it is necessary to get surely corresponding version of the central switchboard.
  2. To open a cover and to disconnect loops.
  3. To press on fixing brackets on the right and at the left on a plug-in element – actually central the switchboard and to pull out a plug-in element with the connected wires.
  4. To switch plugs one by one with old to the new device.
  5. Again to establish a plug-in element in a frame.
  6. To remove a shelf at the left under the dashboard and to check, whether everything wires were switched.

 Help: the cover of the central switchboard has to be closed, differently during a driving on feet of the driver drafts will walk.