GM Service Manual Online
For 1990-2009 cars only

This feature controls the brightness of the instrument panel lights. The instrument panel brightness thumbwheel is located next to the exterior lamp control.

(Instrument Panel Brightness): Turn the thumbwheel up or down to brighten or dim the instrument panel lights and the radio display. The instrument panel lights, cluster, and radio display do not dim to complete darkness. Turn the thumbwheel all the way up to turn the dome lamps on.