Horn
Press 
on the steering wheel pad to sound the horn.
See also:
Store a Name Tag for Speed Dialing
1. Push . System responds:
“OnStar ready.” 2. Say “Store.” System responds:
“Please say the number you would like to store.” 3. Say the entire number without pausing. System responds:
...
Tire Sealant and Compressor Kit
WARNING
Idling a vehicle in an enclosed area with poor ventilation is dangerous. Engine exhaust may enter the vehicle. Engine exhaust contains carbon monoxide (CO) which cannot be seen or smelled.
I ...
Airbag System Check
The airbag system does not need regularly scheduled maintenance or replacement. Make sure the airbag readiness light is working.
See Airbag Readiness Light on page 5‑16 for more information.
N ...