Body Control Module (BCM)
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 BCM controls the operation of the perimeter alarm. The BCM receives direct input from all the ajar switches, the hood switch, and the door lock control switches. It receives messages from the RFA module over the MS-CAN for the lock/unlock status of the vehicle.
If the perimeter alarm is armed and the BCM receives an input indicating an unauthorized entry into the vehicle, the BCM activates the perimeter alarm. When the perimeter alarm is activated, the horn sounds and both the turn signals and courtesy lights flash in regular intervals.