System Description
The horn system consists of the following components:
| The horn switch is part of the inflatable restraint steering wheel module. |
• | The body control module (BCM) |
• | The vehicle interface unit (VIU) |
System Operation
The vehicle horn system is activated under the following conditions:
• | The horn switch is depressed. |
• | On vehicles equipped with content theft deterrent (UA6), the body control
module may command the horn on. The BCM commands the horn ON under any
of the following conditions: |
- | 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
in Keyless Entry. |
Circuit Operation
Battery positive voltage is applied at all times to the horn relay coil and
the horn relay switch. Pressing the horn switch applies ground to the horn relay control
circuit. On vehicles equipped with UA6, 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 horn through
the horn control circuit. The horn sounds as long as ground is applied to the horn
relay control circuit.