Body Control Module (BCM)
WARNING: This page is about a different car, the 2016 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
The BCM is used to calculate the illumination dimming level for all illumination sources. The illumination voltage circuit from the BCM is protected by a Field Effect Transistor (FET). This is used to turn the output off to protect the BCM from damage in the event that an excessive current draw is detected on the illumination voltage circuit. For a full description of Field Effect Transistor (FET) protection, Refer to: Module Controlled Functions - System Operation and Component Description .