Dimmable Backlighting

The dimmable backlighting is controlled by the BCM based on the ambient light level and the illumination dimmer position. When the headlamps or parking lamps are on, the BCM monitors the non-networked input from the instrument panel dimmer switch and sends a pulse-width modulated voltage to the non-networked dimmable switches and components on two circuits. The BCM supplies and controls the start/stop switch backlighting illumination on a non-network circuit independent from the other non-network dimmable components. If a fault is detected by the BCM on a dimmable illumination output circuit, the BCM sets a DTC and disables the circuit function until the fault is cleared and an ignition cycle takes place.

The BCM also sends a message over the MS-CAN to the HVAC (EATC) and to the IPC to control the backlighting intensity level. The IPC sends the illumination dimming level message to the APIM, FCIM (touchscreen only) and FCDIM on the Infotainment Controller Area Network (I-CAN) based on the input received from the BCM over the MS-CAN. The receiving modules use the illumination dimming level message to determine the backlighting intensity of integral illumination sources. If the receiving module does not receive the backlighting status message from the BCM or from the IPC or if the data received is deemed invalid for more than 5 seconds, the receiving module sets a missing message related DTC in continuous memory and defaults the backlighting to full nighttime intensity.

When the headlamps or parking lamps are off and the light sensor detects daytime conditions, the IPC, the FCDIM and the FDIM are illuminated to full brightness.

If the exterior lamps are activated during the daytime on vehicles 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 input signals of dimming level 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 night illumination level.

On vehicles not equipped with a touchscreen, the FCDIM forwards the illumination dimming level message to the FCIM via the LIN circuit.

On vehicles equipped with a touchscreen, the APIM sends the illumination dimming level message to the FDIM.

On any audio system, if the light sensor detects nighttime conditions and the parking lamps or headlamps are on, only the ON/OFF volume button and the hazard/door lock switch are illuminated on the FCIM until the audio unit is turned on. If the audio unit is on while the ignition is in the OFF position and the parking lamps or headlamps are off but the light sensor detects nighttime conditions, it is possible to control the dimming level of the FCDIM, FCIM and FDIM.

On some vehicles equipped with an ambient light sensor and FCDIM, the FCDIM provides a setup menu to select manual or automatic illumination levels based on ambient light levels. For additional information, refer to the Owner's Literature.