Horn: Description and Operation

Horns System Description and Operation

System Description

The horn system consists of the following components:

* F51UA 15A fuse
* Underhood fuse block (contains a non-serviceable PCB Horn relay)
* Horn switch
* Horn
* Body control module (BCM)

System Operation

* The vehicle horn is activated whenever 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 Content Theft Deterrent (CTD) Description and Operation (Content Theft Deterrent (CTD)).
- 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 (Description and Operation).

Circuit Operation

The BCM controls the horn operation, when the horn switch is pressed, it closes a switch pulling the horn signal circuit low. When the BCM detects the drop in voltage in the horn switch signal circuit, it energizes the PCB Horn relay which provides B+ voltage to the horn control circuit, sounding the horn.

When the vehicle is in the Off Power Mode the BCM will attempt to detect a stuck or continuously activated horn switch. When enabled, activation of the horn will be limited to 10 seconds to protect the horn from excessive use.