GMC Terrain: Exterior Lighting / Automatic Headlamp System
When the exterior lamp control is set to AUTO and it is dark enough outside, the headlamps come on automatically.
There is a light sensor on top of the instrument panel. Do not cover the sensor; otherwise the headlamps will come on when they are not needed.
The system may also turn on the headlamps when driving through a parking garage or tunnel.
When it is bright enough outside, the headlamps will turn off or may change to Daytime Running Lamps (DRL).
The automatic headlamp system
turns off when the exterior lamp
control is turned to 
or the
ignition
is off.
Lights On with Wipers
If the windshield wipers are
activated in daylight with the engine
on, and the exterior lamp control is
in AUTO, the headlamps, parking
lamps, and other exterior lamps
come on. The transition time for the
lamps coming on varies based on
wiper speed. When the wipers are
not operating, these lamps turn off.
Move the exterior lamp control to 
or 
to disable this feature.
Daytime Running Lamps (DRL)
DRL can make it easier for others to
see the front of your vehicle during
the day. Fully functional DRL are
required on all vehicles first sold in
Canada...
Hazard Warning Flashers
: Press to make the front and
rear turn signal lamps flash on and
off. This warns others that you are
having trouble.
Press again to turn the
flashers off...
Other information:
GMC Terrain 2018-2025 Owners Manual: Engine Heater
Warning Do not plug in the engine block heater while the vehicle is parked in a garage or under a carport. Property damage or personal injury may result. Always park the vehicle in a clear open area away from buildings or structures. The engine heater, if available, can help in cold weather conditions at or below −18 °C (0 °F) for easier starting and better fuel economy during engine..
GMC Terrain 2018-2025 Owners Manual: Additional Factors Affecting System Operation
Seat belts help keep the passenger in position on the seat during vehicle maneuvers and braking, which helps the passenger sensing system maintain the passenger airbag status. See “Seat Belts” and “Child Restraints” in the Index for additional information about the importance of proper restraint use. A thick layer of additional material, such as a blanket or cushion, or aftermark..