Horn System (Service Information): Description

An electrically-operated horn system is standard factory-installed equipment in this vehicle. Depressing the Driver Airbag (DAB) trim cover in the center of the steering wheel actuates the horn switch contacts, which provides the vehicle operator with a convenient, audible signaling device that can be used to alert pedestrians or the operators of other vehicles in near proximity.

The Body Control Module (BCM) serves as the controller for the horn system, which also allows the BCM to utilize the horn system when providing audible outputs to support other vehicle features such as the horn chirp verification of the Remote Keyless Entry (RKE) and Remote Start systems, as well as the pulsing horn deterrent feature of the optional Vehicle Theft Alarm (VTA) and the RKE Panic mode.

The horn system includes the following major components, which are described in further detail elsewhere in this service information:

• Horn Relay  - The horn relay is an International Standards Organization (ISO) micro relay located within the front Power Distribution Center (PDC). The front PDC is located on the top of the right front wheel house forward of the right strut tower within the engine compartment.
• Horns  - The horns are each located on an integral mounting bracket secured to the right or left forward-facing surface of the Front End Module (FEM) carrier, just in front of the upper radiator cross member. The front fascia needs to be removed to gain access to the horns for service.
• Horn Switch Plate  - The floating horn switch plate is secured to the back of the DAB module within the steering wheel hub cavity and also serves as the mounting bracket between the DAB and the steering wheel.

Certain functions and features of the horn system rely upon resources shared with other electronic modules in the vehicle over the Controller Area Network (CAN) data bus. Other electronic modules in the vehicle that may affect horn system operation are:

• Body Control Module  - The BCM is located on the right cowl side inner (kick) panel within the passenger compartment, where it is concealed behind the cowl side inner trim and the instrument panel. Refer to MODULE, BODY CONTROL (BCM), DESCRIPTION .
• Radio Frequency Hub Module  - The Radio Frequency Hub Module (RFHM) is located near the center of the shelf support behind the rear seat back and is concealed beneath the package tray interior trim. Refer to MODULE, RADIO FREQUENCY (RF HUB), DESCRIPTION .
• Steering Column Control Module  - The Steering Column Control Module (SCCM) is located near the top of the steering column directly below the steering wheel. Refer to MODULE, STEERING COLUMN CONTROL (SCCM), DESCRIPTION .

The BCM, the RFHM and the SCCM each contain a microcontroller and programming that allow them to communicate with each other and other electronic modules in the vehicle using the Controller Area Network (CAN) data bus. Refer to COMMUNICATION, DESCRIPTION .

Hard wired circuitry connects the various horn system components to each other through the electrical system of the vehicle. These hard wired circuits are integral to several wire harnesses, which are routed throughout the vehicle and retained by many different methods. These circuits may be connected to each other and to the vehicle electrical system through the use of a combination of soldered splices, splice block connectors and many different types of wire harness terminal connectors and insulators. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, further details on wire harness routing and retention as well as pin out and location views for the various wire harness connectors, splices and grounds.