System Operation

Instrument Cluster and Panel Illumination

System Operation

System Diagram





Network Message Chart

BCM (Body Control Module) Network Input Messages





ATCM (All Terrain Control Module), HVAC (Heating, Ventilation, and Air Conditioning) Module and IPC (Instrument Panel Cluster) Network Input Messages





ACM (Audio Control Module), APIM (Accessory Protocol Interface Module), FCIM (Front Controls Interface Module) and FCDIM (Front Control/Display Interface Module) Network Input Messages






Dimmable Backlighting

The dimmable switches and components are illuminated when the parking lamps are on. The instrument panel dimmer switch, which is integral to the FLM (Front Lighting Control Module), controls all dimmable interior illuminated components. On vehicles equipped with autolamps, if the exterior lamps are activated during the daytime, the message center illumination remains at full intensity and does not dim from the instrument panel dimmer switch during this condition. If the vehicle travels under a bridge or a tunnel, the low level of ambient light causes the illumination level of the message center to change to the level set by the instrument panel dimmer switch. The message center illumination changes back to full intensity when the intense ambient light is restored.When the parking lamps are on, the BCM (Body Control Module) sends a pulse-width modulated voltage to the hardwired dimmable components and switches based on input received from the instrument panel dimmer switch (part of the FLM (Front Lighting Control Module)).
The BCM (Body Control Module) also sends the illumination dimming level message over the network. If a receiving module receives invalid backlighting data from the BCM (Body Control Module) for 5 seconds or less, the receiving module defaults the backlighting to the last setting.
If the receiving module does not receive the backlighting status message from the BCM (Body Control Module) or if the data received is deemed invalid for more than 5 seconds, the receiving module sets a DTC (Diagnostic Trouble Code) in continuous memory and defaults the backlighting to full nighttime intensity.

Non-Dimmable Backlighting

When the accessory delay relay is energized, switched voltage is supplied to the window control and door lock control switches. REFER to Delayed Accessory Power .

Field-Effect Transistor (FET) Protection

REFER to Field Effect Transistor (FET) Protection .