1995 GMC Sonoma Owner's Manual - Page 92

Dome Lamp The dome lampwill come on when the side doors are opened. You can also turn the dome lamp onby turning the INT LIGHTS dimmer switch up until it clicks. Mirrors Inside Mirror Press the tab under the mirror to reduce glare from headlamps behind you. If your vehicle has optional map lamps, they will automatically come on for approximately 20 seconds when either frontdoor is opened orunlocked with the Keyless Entry system, if so equipped, oruntil the ignition is turned to RUN or ACC. The lights will also stay on for approximately 15 seconds after you exit the vehicle. They will also stay on for 15 seconds when the interior light switch on the dash is turned on then off, while the ignition is off. 2-46