Horn System (Service Information): Description

An electrically-operated horn system is standard factory-installed equipment in this vehicle. Pressing 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 RKE Panic mode.

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

• Horn Relays  - One horn relay is soldered to the Printed Circuit Board (PCB) located within the Power Distribution Center (PDC) and is not serviceable. The PDC is located in the engine compartment behind the battery. A second horn relay is in series with the PDC horn relay and is soldered to a PCB located in the BCM, which is concealed within the instrument panel behind a fuse access panel outboard of the steering column. The horn relay in the BCM supplies battery current to the control side of the PDC horn relay.
• Horns  - The standard dual-note horns are located on a bracket secured to the Front End Module (FEM) carrier near the center of the upper radiator crossmember, just behind the radiator grille panel. The appearance shield covering the FEM carrier, the crossmember and the outboard sides of the cooling module must 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 housing 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 Local Interface Network (LIN) data bus and 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 concealed within the instrument panel outboard of the steering column. The BCM is both a LIN bus master node and a gateway to the CAN data bus. Refer to MODULE, BODY CONTROL (BCM), DESCRIPTION .
• Radio Frequency Hub Module  - The Radio Frequency Hub (RFH) Module is located on the upper right D-pillar near the liftgate opening upper header where it is concealed behind the interior trim. Refer to MODULE, RADIO FREQUENCY (RF HUB), DESCRIPTION .

The BCM and the RFH module each contain a microcontroller and programming that allow them to communicate with each other and other electronic modules in the vehicle using the CAN data bus. Refer to COMMUNICATION, DESCRIPTION .

Hardwired circuitry connects the various horn system components to each other through the electrical system of the vehicle. These hardwired 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 appropriate SYSTEM WIRING DIAGRAMS, details of wire harness routing and retention, connector pin-out information and location views for the various wire harness connectors, splices and grounds. For proper wire repair, and connector repair procedures. Refer to STANDARD PROCEDURE or REMOVAL or INSTALLATION .