GMC 1996 Safari Owner's Manual page 193

Section 5 Problems on the Road
Here you'll find what to do about some problems that
can occur on the road.
Hazard Warning Flashers
YOLK 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.
Press the button down to make your rront 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.
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