Horn
Pressa 
on the steering wheel pad
to sound the horn.
See also:
Turn and Lane-Change Signals
An arrow on the instrument panel cluster will flash in the direction of the turn
or lane change.
Move the lever all the way up or down to signal a turn.
Raise or lower the lever until the arrow ...
Diagnostics
OnStar Vehicle Diagnostics will perform a vehicle check every month. It will
check the engine, transmission, antilock brakes, and major vehicle systems. It also
checks the tire pressures, if the v ...
Add-on Electrical Equipment
The OnStar system is integrated into the electrical architecture of the vehicle.
Do not add any electrical equipment. See Add-On Electrical Equipment on page 9‑64.
Added electrical equipment ...