GMC 2009 Sierra - Manual (Page 142)

Hazard Warning Flashers
The hazard warning flashers warn others. They also let
police know you have a problem.
The hazard warning
flasher button is located
on top of the steering
column.
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.
The hazard warning flashers work no matter what
ignition position the key is in, and even if the key is not
in the ignition.
When the hazard warning flashers are on, your vehicle’s
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.
Horn
To sound the horn, press the horn symbols located on
the steering wheel.
Tilt Wheel
The tilt wheel lets you adjust the steering wheel before
you drive. Raise it to the highest level to give your
legs more room when exiting or entering the vehicle.
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