GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Cobalt 🢒 Vehicle Control Systems 🢒 Computer/Integrating Systems 🢒 Horns System Description and Operation

System Description

The horn system consists of the following components:

    • HORN fuse
    • Horn relay
    • Horn button
    • Horn assembly
    • Body control module (BCM)

System Operation

The body control module (BCM) commands the horns ON. The BCM commands the horns ON under any of the following conditions:

    • When the horn button is depressed
    • 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.

Circuit Operation

Battery positive voltage is applied at all times to the horn relay coil and the horn relay switch. Pressing the horn button applies ground to the horn switch signal circuit. The body control module (BCM) applies 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.