GMC Sierra Owners Manual
For vehicles with reading lamps, they are located on the overhead console.
To turn on the reading lamps, press the button located next to each lamp. To turn them off, press the button again.
The vehicle may also have reading lamps in other locations. To turn the lamps on or off, press the button located next to the lamp.
If the vehicle has a DVD Rear Seat Entertainment (RSE) system, press the lamp lenses to turn the lamps on or off.
The lamps are fixed and cannot be adjusted.