Audio Front Control Module (ACM) Illumination
WARNING: This page is about a different car, the 2012 Ford Pickup, 2012 Ford F550 Super Duty, 2012 Ford F450 Super Duty, and 2012 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
The base (AM/FM) ACM has a hardwired illumination circuit from the Body Control Module (BCM). For all other ACMs, the illumination signal is received via the MS-CAN.