Getting to know the electrical circuit (VW Passat B3)

To provide all consumers of electrical energy with electricity, up to 1000 m of wires are laid in a passenger car.

If you want to detect a fault in the electrical system or install additional electrical components, you cannot do without an electrical diagram. Using the diagram, you can detect the presence of electric current and wire connectors. The corresponding electrical circuit must be closed, otherwise there will be no electric current in it. It is not enough, for example, to supply voltage to the positive terminal of the headlight if the electrical circuit is not simultaneously closed through the ground.

Therefore, the battery ground wire is also connected to the car body. However, sometimes this ground connection is not sufficient, and the corresponding consumer is connected to the ground directly by a wire, which is usually painted brown. A switch, relay, fuses, measuring instruments, electric motors or other electrical components can be connected in a separate electrical circuit. In order to be able to connect these components correctly, the individual contacts have corresponding markings.

In order to visually organize the interweaving of wires, at least in the electrical diagram, individual current lines are arranged vertically next to each other and numbered.



The vertical lines approach the mostly greyed out area at the top. This area symbolizes the relay board with the fuse holders and, at the same time, the positive connectors of the electrical circuit. First of all, the internal ground wire (terminal 31) is also located on the relay board. The fine lines on the field explain how and which electrical circuits inside the relay board are connected to each other. At the bottom, the electrical circuit line connects to the horizontal pin, symbolizing the connection to the car body. The connection to the ground is usually made directly through the body or via a wire from the ground connector located on the body.

When an electrical circuit ends with a square containing a number, that number indicates the number of the current line to which this electrical circuit is then connected.

The most reasonable way to use an electrical circuit is to proceed as follows:

First, look for the corresponding part on the diagram, for example, the switch of the heating system fan. In the right column next to the part designation on the diagram, the number of the corresponding current line is indicated, which flows into the horizontal line at the bottom.

In order to be able to read an electrical diagram, it is necessary to know the designations of many parts, in addition, it is necessary to know the most important conventional graphic symbols.

Letter designations of the most important parts:

For more accurate recognition, digital symbols are added to the letter symbols.


Relays and electronic control units are usually shown in grey. The lines inside them refer to the internal wiring. They show how the relays and other electrical/electronic components are connected to each other and to the relay board.

The number in the black square indicates the location of the relay on the relay board with the fuse holder. Directly next to the designated relay is the contact designation.

Example: If the contacts on the electrical diagram are marked with numbers 17/87, then the number 17 is the designation of the terminal on the relay board, and 87 is the designation of the terminal on the relay/control unit.

The terminal designations are given in accordance with the German industrial standard (DIN).

The most important letter designations of terminals:

Terminal 30. Battery voltage is always applied to this terminal. The wires are usually red or red with colored stripes. Terminal 31 is connected to ground. Ground wires are usually brown.

Terminal 15 is powered via the ignition switch. Current flows through the wires only when the ignition is on. The wires are usually green or green with colored stripes.

Terminal X is also supplied with power only when the ignition is on, but the power supply is interrupted when the starter is engaged. This ensures that the ignition system receives full battery power during engine starting. All significant current consumers are connected to this electrical circuit. The high beam headlights are also supplied with current via this terminal. Thus, when the high beam is on and the ignition is off, the parking lights are automatically switched on.

Construction of electrical circuits

Electrical diagrams VW PASSAT, model 1995

Due to lack of space, it is not possible to consider every electrical diagram for a separate engine variant or car model, as well as for each model year. With a new edition, up-to-date electrical diagrams are published as needed, which can also be used as a reference by owners of older models.

Note: For central distribution/relay location, see chapter "Electrical equipment system".

Alternator, battery, starter

Designations in the electrical diagram shown on this page.

The relay board with fuse holder is indicated by the grey field.

Decoding the colors of the wires:

• ge — yellow
• ws — white
• ro — red
• li — purple
• bl — blue
• gr — gray
• gn — green
• br — brown
• sw — black

Consumer circuit with wire supply: All switches and contacts are shown in a mechanically idle state.

(The original can be found at vwmanual.ru)

Vehicle weight: Numbers in circles indicate installation location (see explanations below the diagram).

Electrical circuit no: For ease of reference (see explanations below the diagram).

Explanations below the diagram

All electrical diagrams use the same symbols for the same parts. For example, A is always a battery.

A - battery - 4
B - starter - 7-8
C - alternating current generator.. 1-2
C1 - voltage regulator - 1-2
T1f - plug connector, 1-pin, in the engine compartment on the right.. 1
T1r - Plug connector, 1-pin, behind the relay board.. 2

Designations in circles

1 - ground jumper, battery - body - 5
2 - ground jumper, gearbox - body - 6
30 - connection to ground "1", next to the relay board - 2
119 - connection to ground "2", in the headlight wiring harness - 4

Electrical diagrams location