1999 Cadillac DeVille Owner's Manual - Page 240

yellowblue Hazard Warning Flashers Press the button in to make the front and rear turn signal lamps flash on and off. This light on the instrument panel will flash, indicating that the hazard warning flashers are on. Your hazard warning flashers let you 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 flashers will work once the button is pressed in regardless of the ignition key position. 5-2