For 1990-2009 cars

### System Description

The horn system consists of the following components:

• | Horn fuse

• | Horn switch

• | Horn

• | Right steering wheel control switch

• | Steering wheel module

• | Underhood fuse block

### System Operation

• | The vehicle horn is activated whenever the horn switch is depressed.

• | The underhood fuse block commands the horn to sound 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.

- | When the OnStar® system is used to sound the horn if equipped. For further information, refer to OnStar Description and Operation.

### Circuit Operation

The right steering wheel control switch monitors the horn switch signal circuit, when the horn pad is pressed, the right steering wheel control switch detects the drop in the horn switch signal circuit and sends a serial data message to the underhood fuse block which commands the horn to sound.