System Operation
Instrument Cluster and Panel Illumination
System Operation
System Diagram
Network Message Chart
IPC (Instrument Panel Cluster) Network Input Messages
APIM (Accessory Protocol Interface Module), FCIM (Front Controls Interface Module) and FCDIM (Front Control/Display Interface Module) Network Input Messages
BCM (Body Control Module) Network Input Messages
DDM (Driver Door Module), Passenger Door Module (PDM), IPM-B (Image Processing Module - B)
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 headlamp switch, 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 through 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.
If the IPC (Instrument Panel Cluster) does not receive the input signals of dimming level or ambient light level for up to 5 seconds, the last valid received state of these signals is assumed. If the IPC (Instrument Panel Cluster) receives invalid or no signals for more than 5 seconds, it assumes full night illumination level.
The IPC (Instrument Panel Cluster) sends the illumination dimming level message over the network. The receiving modules provide illumination to internal or external hard-wired illumination circuits. The BCM (Body Control Module) sends pulse-width modulated voltage to the hard-wired dimmable components and switches.
If the receiving module does not receive the backlighting status message from the IPC (Instrument Panel Cluster) or the BCM (Body Control Module) (through gateway function), 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 night time intensity.
Field-Effect Transistor (FET) Protection
REFER to Field Effect Transistor (FET) Protection .