Section 2727 (System Wiring Diagrams - F150): Radio
WARNING: This page is about a different car, the 2002 Ford Pickup. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Base Radio Circuit
Fig 2: Premium Sound Radio Circuit, W/ Rear Entertainment (1 of 2)
Fig 3: Premium Sound Radio Circuit, W/ Rear Entertainment (2 of 2)
Fig 4: Premium Sound Radio Circuit, W/O Rear Entertainment