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FIGURE 36-36
Typical automotive switches.

A switch is an electrical device used to turn the current on and off in a circuit. When turned off, switches open the circuit, stopping current flow; when turned on, they close the circuit, allowing current to flow. For example, switch off—light goes out; switch on—light comes on. There are many different types and configurations of switches, including toggle switches, push-button switches, and specialty switches for turn signal indicators and windshield wipers Figure 36-36. The most basic switches have only two terminals and are simply on or off.

More complex switches have many terminals and contacts inside them to switch a number of circuits at the same time. The turn signal switch is an example of a more complex switch. It has three positions: center for off, pushed in one direction for the left turn signals, pushed in the other direction for the right turn signals. Circuit or schematic diagrams show switches, their contacts, and the surrounding circuits so that the technician can identify how they operate in a circuit. The terminals on the switch are often numbered or lettered to indicate the correct way of connecting them into their circuits and to show the mating connectors in the wiring diagrams.