Circuit Operation - Interior Lights Dimming

The headlamp and I/P lamp dimmer switch controls the brightness of the incandescent lamps and Vacuum Fluorescent (VF) displays. The incandescent lamps are located in various components (see schematics) and the VF display is located in the radio, PRNDL, driver information display (if equipped) and radio rear speaker amplifier (if equipped).

Incandescent Dimming
The brightness of the incandescent lamps is determined by a variable voltage signal produced by the headlamp and I/P lamp dimmer switch through circuit 8.

Vacuum Fluorescent (VF) Dimming
The brightness of the VF display is controlled by two signals, the park lamp signal (circuit 9) and the VF Dim signal (circuit 308). With the park lamps on, the VF display of the radio, PRNDL, driver information display (if equipped) and radio rear seat audio control (if equipped), will dim for nighttime viewing. When the park lamps on signal is not present (park lamps are off), the VF display is at high brightness for daytime viewing. When the park lamps are on, the headlamp and I/P lamp dimmer switch provides a dimming signal through circuit 308 which controls the brightness of the VF display when the headlamp and I/P lamp dimmer switch is adjusted.