GMC Sierra 2014 Owner's Manual page 22

1-16 In Brief
To change the dome lamp settings,
press the following:
OFF: Turns the lamps off, even
when a door is open.
DOOR: The lamps come on
automatically when a door is
opened.
ON: Turns all dome lamps on.
Reading Lamps
There are reading lamps in the
overhead console and the headliner,
if equipped. To operate, the ignition
must be in the ACC/ACCESSORY
or ON/RUN position or using
Retained Accessory Power (RAP).
Press or next to each reading
lamp to turn it on or off.
Exterior Lighting
The exterior lamp control is on the
instrument panel to the left of the
steering wheel.
O
: Turns off the automatic
headlamps and Daytime Running
Lamps (DRL). Turn the headlamp
control to the off position again to
turn the automatic headlamps or
DRL back on.
For vehicles first sold in Canada, off
will only work when the vehicle is in
P (Park).