Ignition Switch
WARNING: This page is about a different car, the 2017 Lincoln Navigator and 2017 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.
The ignition switch is controlled by the ignition lock cylinder with a key. When the ignition lock cylinder is turned using the key, a mechanical connection positions the ignition switch to the selected position and allows the ignition switch to send voltage to specific components. The ignition switch sends voltage to the BCM and PCM during engine cranking.