Dimmable Illumination

WARNING: This page is about a different car, the 2017 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

The BCM sends 2 voltage signals to the headlamp switch, one for the brightness increase and the other for brightness decrease. The illumination dimming level is controlled by the BCM. Based on the input from the instrument panel dimmer switch (integral to the headlamp switch), the BCM calculates the dimming level.

When the autolamp feature activates during the daytime, the message center illumination remains at full intensity and does not dim from the instrument panel dimmer switch. If the vehicle travels under a bridge or through a tunnel and a low level of ambient light is detected, the illumination brightness of the message center changes to the last level set by BCM. The message center illumination changes back to full intensity when the intense ambient light is restored.

Wired Components

The BCM provides PWM voltage to the following components for backlighting:

NOTE: Some components are optional and are not equipped on every vehicle.

Headlamp switch
Steering wheel control switches
Overhead console
Hazard flasher switch
Heated seat switch (rear seats)
Parking brake switch
Front luggage compartment lid release switch
Ignition switch

Networked Message Components

The BCM sends the illumination brightness level message to the following modules:

NOTE: Some components are optional and are not equipped on every vehicle.

ACM
APIM
FCIM
GSM
IPC

The receiving modules use the illumination brightness level message to set the backlighting intensity of internal illumination sources. If a module does not receive the illumination brightness level message or the data received is deemed invalid, the module defaults to full nighttime intensity.

Additionally, if the IPC does not receive the ambient light level message from the BCM for up to 5 seconds, the IPC illumination remains at the last level based on the last message received.