Audi A4

since 1994 release

Repair and operation of the car

A4 Audi
+ 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

З дворняги – у кінозірки: як проходить кастинг тварин

Switching relay

Function of the switching relay


  1. At inclusion of a certain consumer in the switching relay "switching current", arriving on the plug 86, closes an electric chain to the plug 85 (weight).
  2. As a result of it the electromagnetic coil attracts powerful contact, counteracting spring pressure, and thus closes an electric chain for passing of "working current".
  3. To avoid power failure, working current moves in the short way on the plug of 30 relays and from there, at the closed contacts of the switch, via the plug 87 further to the consumer.
  4. Sometimes there is one more plug 87a. It is closely connected with the plug 87, i.e. it has the same function.

Search of malfunctions in the switching relay


  1. On the plug 30 always there has to be tension (giving of tension for working contact).
  2. To check giving of tension, take out the relay and knock with a needle of a control lamp on the plug 30 in a relay socle. There is no current: defect in a tokopodvodyashchy wire.
  3. If the corresponding switch is switched on, on the plug 86 there has to be tension, (giving of tension on the relay coil).
  4. For check knock on the plug 86 in a relay socle with a needle of a control lamp.
  5. There is no current: defect in a wire or in the switch.
  6. The plug 85 is a weight wire to the coil. A control lamp check the accumulator – + (for example, the plug 30).
  7. The coil of the relay is checked on the removed relay: connect the plug 86 to plus of the accumulator and the plug 85 with a weight. The electromagnetic coil has to attract contact of the relay with a distinct sound, otherwise the relay is defective.

The temporary help at the faulty switching relay


  1. Take out the relay from the socket.
  2. Close the plug 30 and 87 in a relay nest an office paper clip or a piece of a wire. Thanks to it the corresponding consumer will receive a direct current.
  3. That to switch off it, disconnect the short-circuiting crossing point as in this case this consumer will close.