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.
Fig 1: Power Liftgate/Retractable Running Boards Wiring Diagram (1 of 6)
Courtesy of FORD MOTOR COMPANY
Fig 2: Power Liftgate/Retractable Running Boards Wiring Diagram (2 of 6)
Courtesy of FORD MOTOR COMPANY
Fig 3: Power Liftgate/Retractable Running Boards Wiring Diagram (3 of 6)
Courtesy of FORD MOTOR COMPANY
Fig 4: Power Liftgate/Retractable Running Boards Wiring Diagram (4 of 6)
Courtesy of FORD MOTOR COMPANY
Fig 5: Power Liftgate/Retractable Running Boards Wiring Diagram (5 of 6)
Courtesy of FORD MOTOR COMPANY
Fig 6: Power Liftgate/Retractable Running Boards Wiring Diagram (6 of 6)