Horn
Press 
on the steering wheel pad to sound the horn.
See also:
Reporting Safety Defects to General Motors
In addition to notifying NHTSA (or Transport Canada) in a situation like
this, notify General Motors.
Call 1-800-458-8006, or write:
Cadillac Customer Assistance
Center
Cadillac Motor Car Div ...
Starting the Engine Using Remote Start
To start the engine using the remote
start feature:
1. Aim the transmitter at the vehicle
and press and release on the
transmitter.
2. Press and hold for at least
four seconds or until the ...
How OnStar Service Works
Automatic Crash Response,
Emergency Services, Crisis Assist,
Stolen Vehicle Assistance, Vehicle
Diagnostics, Remote Door Unlock,
Roadside Assistance, Turn-by-Turn
Navigation, and Hands-Free ...