Horns and Pedestrian Alerts
2-15
Description and Operation
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 assembly
•
Body control module (BCM)
3270443
System Operation
The vehicle horn system is activated under the
following conditions:
•
When the horn switch is depressed
•
The BCM commands the horns ON under any
of the following conditions:
–
When the content theft deterrent system detects
a vehicle intrusion
—
For further information refer
to Theft Systems Description and Operation.
–
When the panic button is depressed on the
remote control door lock transmitter
—
For further
information refer to Keyless Entry System
Description and Operation.
–
When the keyless entry system is used to lock
the vehicle, a horn chirp may sound to notify the
driver that the vehicle has been locked. The
notification feature may be enabled or disabled
through personalization. For further information
refer to Keyless Entry System Description and
Operation.
–
When the OnStar
®
system is used to sound the
horns if equipped
—
For further information, refer
to OnStar Description and Operation.
Circuit Operation
Battery positive voltage is applied at all times to the
horn relay coil and the horn relay switch. Pressing
either of the horn switches applies ground to the horn
relay control circuit. The BCM may also apply ground to
the horn relay control circuit as described above. When
the horn relay control circuit is grounded, the horn relay
is energized and battery positive voltage is applied to
the horns through the horn control circuit. The horns
sound as long as ground is applied to the horn relay
control circuit.
2021 - Silverado 4500HD, 5500HD, and 6500HD Electrical Body Builder Manual
