Park Position Detect Switch
WARNING: This page is about a different car, the 2013 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
The park position detect switch is hardwired to the IPC through a single signal circuit. The park position detect switch is hardwired to a separate ground circuit. The IPC provides a battery reference voltage to the park position detect switch. When the selector lever is in PARK (P), the park position detect switch routes the reference voltage to ground, pulling the circuit low to the IPC . When the selector lever is moved out of PARK (P), the park position detect switch opens to ground sending the reference voltage high.