Starting System
WARNING: This page is about a different car, the 2019 Ford F-350 Super Duty and 2019 Ford F-250 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.
The starting system controls the cranking of the engine. When the PCM receives inputs from the ignition switch, transmission (with automatic transmission) or clutch pedal position switch (with manual transmission), run/start relay and the BCM it then energizes the BJB starter relay. When the starter relay is energized it applies power to the starter motor which cranks the engine.