What is the function of the ignition switch?

[DeWilliam]

The function of the ignition switch is to connect or disconnect the starter, ignition, and electrical circuits. The ignition switch typically has four positions: 0 or LOCK, I or ACC, II or ON, and III or START. The ignition switch, which is the switch of the ignition system, can freely open or close the main circuit of the ignition coil and is also applicable to other electrical circuits. Commonly referred to as the master switch, main power switch, or main key, the ignition switch acts as the main gate controlling the entire vehicle's electrical system. It comes in two types: plug-in and rotary knob. The ignition switch consists of a key, key socket, external wires, and contact blades. It is usually installed above the vehicle's front or at the center of the dashboard.