Horn System (Service Information): Description: Description
An electrically-operated horn system is standard factory-installed equipment in this vehicle. A single note system is standard for vehicles manufactured for domestic markets, while a dual note system is used in vehicles manufactured for most export markets. Through the horn switch, either horn system provides the vehicle operator with a convenient, audible signaling device that can be used to gain the attention of pedestrians or to alert other vehicles in close proximity.
On vehicles so equipped, the horn system can also be activated by the Totally Integrated Power Module (TIPM) in response to certain electronic requests from other systems in the vehicle. The Remote Keyless Entry (RKE) system can provide a customer programmable audible horn chirp verification that a valid Lock request was received from the RKE transmitter. The horn system provides the RKE system Panic mode audible alert or deterrent on vehicles so equipped. The horn system also serves as the Vehicle Theft Security System (VTSS) audible alarm in vehicles that are not equipped with the optional siren.
The horn system includes the following major components, which are described in further detail elsewhere in this service information:
- Horn - A low-note horn is located on the outboard side of the left frame rail, just forward of the left front wheel house splash shield in all vehicles. A high-note horn is located on the outboard side of the right frame rail just forward of the right front wheel house splash shield in vehicles so equipped.
- Horn Switch - A floating-type horn switch and mounting plate unit is secured on the back of the Driver AirBag (DAB) housing with four screws. The DAB, horn switch and mounting plate are secured to the steering wheel armature with two screws.
Certain functions and features of the horn system rely upon resources shared with other electronic modules in the vehicle over a Local Interface Network (LIN) data bus as well as over the Controller Area Network (CAN) data bus. Other electronic modules in the vehicle that may affect horn system operation are:
- ElectroMechanical Instrument Cluster - The ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) is located in the instrument panel, directly in front of the driver. In addition to instrumentation, the EMIC provides many electronic interior body control functions and is a Local Interface Network (LIN) master node as well as a gateway to the Controller Area Network (CAN) data bus. Refer to DESCRIPTION .
- Speed Control Switch Pod - The speed control switch pod in the right horizontal spoke bezel of the steering wheel includes a Local Interface Network (LIN) slave node that monitors and transmits the status of the horn switch. Refer to SWITCH, SPEED CONTROL, DESCRIPTION .
- Totally Integrated Power Module - The Totally Integrated Power Module (TIPM) is located in the engine compartment, near the battery. The TIPM also communicates with other electronic modules on the CAN data bus network. Refer to MODULE, TOTALLY INTEGRATED POWER (TIPM), DESCRIPTION .
The EMIC and the TIPM each contain a microcontroller and programming that allow them to communicate with each other using the Controller Area Network (CAN) data bus. In addition the speed control switch pod and the EMIC communicate with each other using a Local Interface Network (LIN) data bus. Refer to COMMUNICATION, DESCRIPTION .
Hard wired circuitry connects the horn system components to 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, to the vehicle electrical system and to the horn system components 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.