Wiring Diagram Fundamentals
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FIGURE 36-58
Typical wiring diagram.

Wiring diagrams, also known as electrical schematics or electrical diagrams, use abstract graphical symbols to represent electrical circuits and their connection or relationship to other components in the system. They are essentially a map of all of the electrical components and their connections Figure 36-58. The wiring on modern vehicles is very complex, with many wires and components interconnected. A single wiring diagram of the whole vehicle would be very difficult to read. To make it easier, the wiring diagrams are split up into systems and subsystems to reduce the complexity on each page. For example, there is a wiring diagram for the starter system, a separate one for the charging system, and others for the engine, transmission, anti-lock brakes, headlights, taillights, and so on.

FIGURE 36-59
Every electrical device and component has a corresponding electrical symbol.

Wiring diagrams contain large amounts of information in the form of lines and symbols Figure 36-59. The technician will need to decode this information by interpreting the symbols and connections and relating them to the actual components on the vehicle. To assist in understanding the wiring diagrams, manufacturers supply keys on the diagrams, which are lists of the component symbols and their names, wiring color codes, harness connectors, and pin numbers. Armed with all of this information, the technician can read the wiring diagram and identify circuits as they relate to the actual components and circuits on the vehicle.