Audi A4

since 1994 release

Manual of the car

Audi A4
+ Running gear
+ Regular servicing
+ Engines
+ Turbo-supercharging
+ System of an exhaust
+ Cooling system
+ Fuel tank and fuel pump
+ Air filter and channels of absorption
+ System of injection
+ Coupling
+ Transmission and main transfer
+ Suspension bracket of wheels and steering
+ Brakes
+ Wheels and tires
- Electrotechnical equipment
   Minus is connected to weight
   The help for orientation in the electrotechnical equipment of the car
   Connections of wires
   Central switching knot
   Support of additional relays
   Box for electronics
   Relay and control units
   Switching relay
   H-contact of the relay of unloading
   Table of the relay and control units
   Safety locks
   Table of safety locks
   + Electric circuits
   + Accumulator
   + Generator
   + Starter
+ System of ignition
+ Lighting
+ Alarm equipment
+ Tools and devices
+ Heating and ventilation
+ Body details
+ Salon
Search of malfunctions
Technical characteristics


Safety locks

Each electric device in the car needs only certain, precisely assigned amount of current. According to this consumption of current in this electric chain, naturally, the cross section of its wire was determined. If consumption of current increases in this electric chain, for example, at the expense of the consumer connected in addition or as a result of short circuit, then the wire is overloaded. At the same time the wire is warmed or is even heated if in time giving of current is not interrupted. It is done by safety locks.

In order that Audi at emergence of defect was not completely deenergized, safety locks are integrated into various electric chains. Though electric chains between the accumulator, the generator, a starter and the lock of ignition safety locks are not controlled.

Replacement of safety locks


  1. If one of shtekerny safety locks has to be replaced, then for these purposes you can use small plastic nippers which are attached to a cover of a box with safety locks (on the left face side of the control panel).
  2. Pay attention to what in Audi A4 is cost by safety locks of the smaller size (tiny fusible), than in the previous models.
  3. If the new safety lock fuses at once, find out, maybe, too weak safety lock is put.
  4. If it not so, then determine by the table of safety locks the connected consumers and check them on one. With it you will be helped by the corresponding electric circuit.
  5. In a doubtful case disconnect everything consumers and again serially connect. The consumer at whose connection the safety lock will fuse was faulty.

Additional safety locks

At a certain expanded complete set on a 8-seater support of additional relays at the left under the control panel auxiliary safety locks are placed. At the same time most often it is about so-called thermosafety locks. These are safety locks which at an overload of an electric chain for a certain time interrupt a current stream, and then again restore connection.

Inside in facing (3) of the left face side of the control panel in a clip there are small plastic nippers (2) to take out safety locks, and a crank (4) for emergency control by a sliding roof. In the drawing placement of safety locks in a box is below shown (1).