Instrument Cluster and Panel Illumination

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

The Instrument Panel Cluster (IPC) and panel illumination system consists of both dimmable and non-dimmable (fixed) illumination sources. The IPC and panel illumination is used to provide backlighting to the instrument panel, switches, and control components when the parking lamps are on.

The BCM provides a Pulse-Width Modulation (PWM) voltage signal to the illumination dimmer switch. This PWM signal is routed through the illumination dimmer switch, Dim Up or Dim Down, then to the SCCM logic control. Based on the occupants selection to increase or decrease the intensity of component illumination, the BCM increases or decreases the voltage signal to the dimmable components. When the BCM senses the voltage signal is low (switch in the lowest setting), the dimmable backlighting intensity is low. When the BCM senses the voltage signal is high (switch in the highest setting), the dimmable backlighting intensity is bright. If the voltage signal is too high (an open circuit or short to voltage), the BCM faults the dimmable backlighting to full nighttime brightness. If the dimmer switch monitoring circuit is short to ground, the BCM interprets this as the lowest setting and sets the backlighting to the lowest intensity level, appearing to be inoperative.

Based on inputs received from the illumination dimmer switch via the SCCM, the BCM sends a message over the network to the backlit modules indicating the backlighting intensity level and a PWM voltage to the hardwired dimmable illumination sources.

For the Expedition equipped with autolamps, if the exterior lamps are activated during daytime sunload conditions, the message center illumination remains at full intensity and does not dim from the illumination dimmer switch. If the vehicle travels under a bridge or through a tunnel, the low level of ambient light causes the illumination of the message center to change to the level set by the illumination dimmer switch. The message center illumination changes back to full intensity when intense ambient light is restored.

For the Navigator, if the exterior lamps are activated during daytime sunload conditions, the message center, the Audio Front Control Module (ACM), the HVAC module remain at full intensity and do not dim from the illumination dimmer switch during this condition. If the vehicle travels under a bridge or through a tunnel, the low level of ambient light causes the illumination of the message center, the ACM, the HVAC module and the switch illumination to change to the level set by the illumination dimmer switch. The message center, the ACM, the HVAC module and the switch illumination change back to full intensity when intense ambient light is restored.

Field-Effect Transistor (FET) protection is used to protect the BCM output drivers from damage in the event that excessive current draw is detected on a BCM output. Each illumination circuit connected to the BCM is separately protected. Multifunction Electronic Modules

The dimmable backlighting system provides dimmable backlighting to the following components:

ACM
HVAC module
Ignition switch
Headlamp switch
Dimmer switch
Steering wheel switches
IPC
Overhead console switches
Floor shifter
Traction control/hazard switch
Four-Wheel Drive (4WD) mode select switch
Window control switches (Navigator only)
Door lock control switches (Navigator only)
Front console ambient illumination (Navigator only)

The fixed backlighting system consists of the following:

Door lock control switches (Expedition only)
Window control switches (Expedition only)