Principles Of Operation

Instrument Cluster and Panel Illumination

Principles of Operation

Dimmable Backlighting

The Lighting Control Module (LCM) generates a variable Pulse Width Modulated (PWM) voltage which is distributed to the dimmable components when the parking lamps are on. Light intensity is adjusted by rotating the instrument panel dimmer switch. The dimmable backlighting components consist of:

- Adjustable pedal switch
- Audio unit
- Traction control switch
- Headlamp switch
- Message center switch
- Rear audio/climate control switch
- Clock
- Front cigar lighter
- RH rear cigar lighter
- LH rear cigar lighter
- Speed control switch
- Audio/climate control switch

The LCM communicates backlighting intensity signals on the Standard Corporate Protocol (SCP) network to the following:

- HVAC module
- Instrument Cluster (IC)

If the headlamps are operated during daylight hours, the light sensor amplifier detects high ambient light levels and signals the LCM to keep illumination levels readable and therefore are non-adjustable on the following components:

- Audio unit
- HVAC module

When the headlamp switch is in the OFF position, the IC internally powers the gauge illumination lamps to full brightness.

Fixed Level Backlighting

The following components have fixed level backlighting that is illuminated when the ignition switch is in the RUN or ACC position:

- Heated seat switches
- Window control switches
- Door lock control switches