Non-Networked Illumination
Based on the illumination dimming level message received from the IPC, the BCM sends a pulse-width modulated voltage to the non-networked components.
Non-Networked Illumination
Networked Illumination
The dimming level of networked modules is determined by the IPC. Based on the ambient light level and the instrument panel dimmer switch position messages from the BCM, the IPC calculates the correct dimming level and sends the illumination dimming level message to the BCM and HVAC module on the Medium Speed Controller Area Network (MS-CAN) and to the APIM, FCIM and FCDIM on the Infotainment Controller Area Network (I-CAN). The BCM also forwards the illumination dimming message from the IPC to the DDM and PDM.
The receiving modules use the illumination dimming level message to determine the backlighting intensity of integral illumination sources. When certain modules do not receive the illumination dimming level message or the data received is deemed invalid, these modules can set a continuous memory DTC and defaults to full daytime intensity.
Networked Illumination
If the exterior lamps are activated during the day and the vehicle is equipped with autolamps, 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 does not receive the dimming level or ambient light level signals for up to 5 seconds, the last valid received state of these signals is assumed. If the IPC receives invalid or no signals for more than 5 seconds, it assumes full daytime illumination level.