Ignition Switch
The electrical switch actuated by a key cylinder or push-button that routes battery power to the starter motor and engine control systems.
The ignition switch is the gatekeeper of a vehicle's electrical system. Located on the steering column or in the dashboard, it is operated when the driver turns the ignition key or presses the start/stop button. This switch directs battery power to different electrical circuits depending on its position (Lock, Accessory, Run, or Start).
In the "Start" position, the switch sends a temporary electrical signal to the starter solenoid, which cranks the engine. In the "Run" position, it supplies continuous power to the engine control module (ECM), fuel pump, ignition coils, and other critical systems required to keep the engine running. In the "Accessory" position, it powers the radio and windows while keeping the engine off.
Worn ignition switches can cause a variety of electrical issues, such as a vehicle that cranks but won't start, sudden stalling while driving, dashboard lights flickering, or electrical accessories failing to turn on. Because a heavy keychain can accelerate wear on key-style ignition cylinders, keeping keychains light is a good preventative measure.