Horn
Press 
on the steering wheel
pad to sound the horn.
See also:
Making Turns
Notice:
Making very sharp turns
while trailering could cause the
trailer to come in contact with the
vehicle. The vehicle could be
damaged. Avoid making very
sharp turns while trailering.
...
Rear Seat Passengers
It is very important for rear seat passengers to
buckle up! Accident statistics show that unbelted
people in the rear seat are hurt more often in
crashes than those who are wearing safety belts.
...
Automatic Crash Response
In a crash, built in sensors can automatically alert an
OnStar advisor who is immediately connected to
the vehicle to see if you need help. ...