For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

California Proposition 65 WarningLoss of Control
Skidding
There are three types of skids that correspond to the vehicle's three control
systems:
Braking Skid — wheels are not rolling.
Steering or Cornering Skid — too much speed or steering in a curve causes
tires to slip and lose cornering force.
Acceleration Skid — too muc ...
Horns System Description and Operation
System Description
The horn system consists of the following components:
HORN fuse
Underhood fuse block (contains PCB horn relay)
Horn switch
Horn
Body control module (BCM)
K84Keyless
Entry
Control
ModuleS33Horn
SwitchK73Telematics
Communication
In ...
Dome Lamp Bulb Replacement
Dome Lamp Bulb Replacement
Callout
Component Name
Preliminary Procedure
Remove the windshield header courtesy lamp. Refer to Windshield Header
Courtesy Lamp Replacement
1
Dome Lamp Bulb
...