Orientation in the electrical system (Audi 100 C4)

Terminal Designations

The motley mix of wires in a car is actually very orderly, because many details of the car electrical system are standard. The numbers on the various parts and cable connections, as well as in the wiring diagrams, have the same meaning in all German and some foreign cars.

Terminal 15 receives power from the ignition switch only when the ignition is on, and in addition to the ignition coil, power is also supplied to those current consumers that should receive it only during direct operation of the car. The wires to terminals 15 have a black sheath, sometimes with additional colored stripes.

Terminal 30 is constantly energized by the positive battery terminal or, if the engine is running, by the alternator. Careless handling of tools can cause short circuits and sparks if the negative battery terminal is not disconnected. This permanently energized wire has a red sheath, with additional colored stripes if necessary.

Terminal 49 is responsible for the turn signal and hazard warning lights.

Terminal 53 supplies power to the windscreen washer system.

Terminal 56 is responsible for supplying power for low beam with yellow and yellow-black wires and for high beam with white and white-black wires.

Terminal 58 is needed for the front and rear side lights and license plate lights. The main color of the wire sheath is gray, with additional color stripes. Terminal 31 is the case or "ground" terminal, with which the power consumer must be connected to the car body so that the electrical circuit is closed. The corresponding wires are provided with a brown sheath.

Designation of electrical connectors

The individual wires are often bundled together in large black-sheathed bundles in the Audi 100, making it difficult to locate a specific wire. Aid in orientation in this case can be obtained from the numerous multi-pin connectors indicated in the wiring diagrams in the next chapter.

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