1997 GMC Sonoma Owner's Manual - Page 200

Hazard Warning Flashers Press the button on top of the steering column all the way down to make your front and rear turn signal lamps flash on and off. Your hazard warning flashers work no matter what position your key is in, and even if the key isn't in. Your hazard warning flashers let you warn others. They also letpolice know you have a problem. Your front and rear turn signal lamps will flash on and off. To turn off the flashers, press the button until the first click and release. When the hazard warning flashers are on, your turn signals won't work. The flashers will stop if YOU step on the brake. Other Warning Devices If you carry reflective triangles, you can set one up at the side of the road about 300 feet (100 m) behind your vehicle. 5-2