Ford Fusion: Instrument Panel and Interior Switches Illumination / Instrument Panel and Interior Switches Illumination - System Operation and Component Description. Description and Operation

System Operation

System Diagram

Network Message Chart

  GSM, FCIM, IPC, ACM, RACM, APIM Network Input Messages

  DDM, PDM Network Input Messages

Dimmable Illumination

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.

Non-Dimmable Illumination

The non-dimmable illumination is on when the delayed accessory relay is active. The delayed accessory relay is active:

• When the ignition is on.
• For up to 10 minutes after the ignition is cycled from on to off and a front door is not opened.

The BCM sends the ignition status to the DDM and the PDM over the network. The DDM and the PDM relay that message to their respective RDM. Based on the ignition status, the DDM, the PDM and each RDM provide voltage to the following components

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

DDM

• Left front door lock control switch
• Fuel filler door release switch

PDM

• Door lock control switch
• Window control switch

RDM

• Window control switch

Component Description

Dimmer Switch

The dimmer switch is a momentary contact switch that is integral to the headlamp switch. The headlamp switch is monitored by the BCM. When the dimmer up or dimmer down button is pressed, the signal from the BCM is routed to ground indicating a request to increase or decrease the illumination brightness level.

BCM

The BCM is the master module in control of the backlighting system.

The BCM requires PMI when replaced. Additionally, carry out the parameter reset procedure and program at least 2 keys.