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 and the Driver Door Module (DDM) generates a variable voltage which is distributed to the dimmable components when the parking lamps are on.

NOTE: The DDM provides the variable voltage to the HVAC module for the brightness level of the display. Light intensity is adjusted by rotating the instrument panel dimmer switch. The dimmable backlighting components consist of:

- Audio unit
- HVAC module (automatic temperature control)
- Climate control assembly (manual temperature control)
- Traction control switch (if equipped)
- Floor shifter (if equipped)
- Headlamp switch
- Instrument Cluster (IC)
- Rear window defrost switch
- Message center switch
- Steering wheel switches

The LCM communicates backlighting intensity level on the Standard Corporate Protocol (SCP) network to the Instrument Cluster (IC) and the DDM. The DDM provides variable voltage to the HVAC module for vehicles equipped with automatic temperature control.

Fixed Level Backlighting

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

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