2007 GMC Yukon Owner's Manual - Page 188

Hazard Warning Flashers The hazard warning flashers warn others. They also let police know you have a problem. Your front and rear turn signal lamps will flash on and off. The hazard warning flasher button is located on top of the steering column. The hazard warning flashers work no matter what ignition position the key is in, and even if the key is not in the ignition. Press the button to make the front and rear turn signal lamps flash on and off. Press the button again to turn the flashers off. When the hazard warning flashers are on, your turn signals will not work. Other Warning Devices If you carry reflective triangles, you can set them up at the side of the road about 300 feet (100 m) behind your vehicle. 188