Incandescent Dimming
WARNING: This page is about a different car, the 2003 Buick Regal and 2003 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
The incandescent lamps become illuminated when the park lamps are on. The brightness of all the incandescent lamps is determined by a variable voltage signal from the dimmer switch and sent through the instrument panel lamp supply voltage 1 circuit. The incandescent lamps are located in various components (see schematics).