Instrument Panel Illumination

INSTRUMENT CLUSTER AND PANEL ILLUMINATION

The instrument cluster and panel illumination is used to provide backlighting to the instrument panel, switches and control components when the headlamp switch is in either the parking lamp ON or headlamp ON position. The level of intensity is adjustable by rotating the instrument panel dimmer switch either up to increase intensity or down to decrease intensity. There are two types of backlighting used in this system, fixed and dimmable. Fixed is non-adjustable backlighting. When the headlamps are in the parking lamp or headlamp ON position, the backlighting is non-adjustable using the instrument panel dimmer switch. The fixed backlighting sources are: driver-side master control window switch, passenger control window switch and driver and passenger door lock controls. The dimmable backlighting is adjustable when the headlamps are in the parking lamp or headlamp ON position, using the instrument panel dimmer switch. The dimmable backlighting sources are: audio switch, transmission selector lever switch, steering wheel control switches, traction control switch, headlamp switch, instrument panel dimmer switch and convertible top switch.

PRINCIPLES OF OPERATION

Instrument Cluster and Panel Lighting - Dimmable
The instrument panel dimmer switch allows the brightness level of backlights and displays to be adjusted dependent upon the headlamp switch position and the instrument panel dimmer switch position. The instrument panel dimmer switch sends a signal to the instrument cluster which then sends a backlighting intensity and dimming curve command over the standard corporate protocol (SCP) link to the front electronic module (FEM). The FEM then sends a pulse width modulated (PWM) dimming signal to the instrument cluster, the dimmable LEDs, and the dimmable incandescents.

When the headlamp switch is in the parking lamps ON, headlamps ON, or the autolamps ON position with the autolamp feature activated, synchronized dimming (of the dimmable components) can be controlled with the instrument panel dimmer switch.

With the key in the RUN position and the headlamp switch in the OFF position, the audio unit, DATC module, tripometer, odometer, and selector lever indicator bezel will be at 100% brightness.

All backlighting will be disabled when the battery saver function has been activated.

Fault Management
The dimmable backlighting will default to 100% intensity if an instrument panel dimmer switch failure occurs.