2011 GMC Acadia Owner's Manual - Page 195

Lighting 6-3 Flash-to-Pass This feature is used to signal to the vehicle ahead that you want to pass. If the headlamps are off or in the low‐beam position, pull the turn signal lever toward you to momentarily switch to high‐beams. Release the lever to turn the high-beam headlamps off. The DRL system makes either the low-beam headlamps come on at a reduced brightness or the DRL lights, for vehicles with High Intensity Discharge (HID) headlamps when the following conditions are met: . darkness of the surroundings. The other lamps that come on with the headlamps will also come on. When it is bright enough outside, the headlamps will go off and the DRL will come on. The regular headlamp system should be turned on when needed. Do not cover the light sensor on top of the instrument panel because it works with the DRL. The ignition is in the ON/RUN position. The exterior lamps control is in AUTO. The engine is running. . Daytime Running Lamps (DRL)/Automatic Headlamp System Daytime Running Lamps (DRL) can make it easier for others to see the front of your vehicle during the day. Fully functional daytime running lamps are required on all vehicles first sold in Canada. . When the DRL are on, the regular headlamps, taillamps, sidemarker, and other lamps will not be on. The instrument panel and cluster will also not be lit. For vehicles with HID headlamps, if the DRL are on and the left or right turn signal lamp is turned on, the left or right DRL will go off. The headlamps automatically change from DRL to the regular headlamps depending on the Hazard Warning Flashers | Hazard Warning Flasher: Press this button located on the instrument panel below the audio system, 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. The turn signals do not work while the hazard warning flashers are on.