Principles of Operation: Notes
WARNING: This page is about a different car, the 2008 Ford RV Cutaway, 2008 Ford Econoline, 2008 Ford E450 Super Duty, and 2008 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
The starting system is electronically controlled by the PCM. The PCM recognizes the signal from the ignition switch and provides a ground for the starter relay. The energized relay provides voltage to the starter solenoid, thereby allowing the starter motor to activate.