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: Driving for Better Fuel Economy
Driving habits can affect fuel mileage. Here are some driving tips to get the best fuel economy possible: Set the climate controls to the desired temperature after the engine is started, or turn them off when not required. Avoid fast starts and accelerate smoothly...
GMC Terrain 2018-2025 Owners Manual: Weather Conditions Affecting ACC
If the interior temperature is extremely high, the instrument cluster may indicate that ACC is temporarily unavailable. This can be caused by extreme hot weather conditions with direct sunlight on the front camera. ACC will return to normal operation once the cabin temperature is lower...
