Audi A4

Since 1994 of release

Repair and car operation

Audi А4
+ Running gear
+ Regular servicing
+ Engines
+ Turbo-supercharging
+ Exhaust system
+ Cooling system
+ Fuel tank and the fuel pump
+ The air filter and channels всасывания
+ Injection system
+ Coupling
+ Transmission and the main transfer
+ Suspension bracket of wheels and steering
+ Brakes
+ Wheels and tyres
- The electrotechnical equipment
   The minus is connected to weight
   The help for orientation in the electrotechnical equipment of the car
   Connections of wires
   The central switching knot
   Support of additional relays
   Box for electronics
   The relay and management blocks
   The switching relay
   H-contact of the relay of unloading
   The table of the relay and management blocks
   Safety locks
   The table of safety locks
   + Electric schemes
   + The accumulator
   + The generator
   + Starter
+ Ignition system
+ Illumination
+ The alarm equipment
+ Tools and devices
+ Heating and ventilation
+ Body details
+ Salon
Search of malfunctions
Technical characteristics

The switching relay

Function of the switching relay


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

Search of malfunctions in the switching relay


  1. On the plug 30 always should be pressure (giving of pressure for working contact).
  2. To check up pressure giving, 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 токоподводящем a wire.
  3. If the corresponding switch on the plug 86 should be pressure, (pressure giving on the relay coil) is included.
  4. For check knock on the plug 86 in a socle of the relay 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 up the accumulator – + (for example, the plug 30).
  7. The relay coil is checked on the removed relay: connect the plug 86 to plus of the accumulator and the plug 85 with weight. The electromagnetic coil should draw relay contact, otherwise the relay with a distinct sound is defective.

The time help at the faulty switching relay


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