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. 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
- Rear window defrost switch
- Message center switch
- Steering wheel speed control switches
- Steering wheel audio/climate control switches

The LCM communicates backlighting intensity signals on the Standard Corporate Protocol (SCP) network to the Instrument Cluster (IC) and the DDM.

Fixed Level Backlighting

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

- Window control switches
- Driver door lock control switch
- Passenger door lock control switch
- Heated seat control switch