WARNING: This page is about a different car, the 2016 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Four Wheel Drive Systems Wiring Diagram (1 of 3)
Courtesy of FORD MOTOR COMPANY
Fig 2: Four Wheel Drive Systems Wiring Diagram (2 of 3)
Courtesy of FORD MOTOR COMPANY
Fig 3: Four Wheel Drive Systems Wiring Diagram (3 of 3)