Horn: Description and Operation

HORN
The standard single, low-note, electromagnetic diaphragm-type horn is secured with a bracket to the right front fender wheel house extension in the engine compartment. The high-note horn for the optional dual-note horn system is connected in parallel with and secured with a bracket just forward of the low-note horn. Each horn is grounded through its wire harness connector and circuit to a ground splice joint connector, and receives battery feed through the closed contacts of the horn relay

The horns cannot be repaired or adjusted and, if faulty or damaged, they must be individually replaced.

Within the two halves of the molded plastic horn housing are a flexible diaphragm, a plunger, an electromagnetic coil and a set of contact points. The diaphragm is secured in suspension around its perimeter by the mating surfaces of the horn housing. The plunger is secured to the center of the diaphragm and extends into the center of the electromagnet. The contact points control the current flow through the electromagnet.

Each horn system is activated by a horn switch concealed beneath the driver side airbag module trim cover in the center of the steering wheel. Depressing the center of the driver side airbag module trim cover closes the horn switch. Closing the horn switch activates the horn relay. The activated horn relay then switches the battery current needed to energize the horn(s).


An electric horn system is standard factory-installed equipment on this model. Two horn systems are offered on this model. The standard equipment horn system features a single low-note electromagnetic horn unit, while the optional dual horn system features one low-note horn unit and one high-note horn unit. Both horn systems use a non-switched source of battery current so that the system will remain functional, regardless of the ignition switch position. The horn system includes the following components:
* Clockspring (Refer to RESTRAINTS/CLOCKSPRING - DESCRIPTION) for more information on this component.
* High-line or premium Central Timer Module (CTM) (Refer to BODY CONTROL/CENTRAL TIMER MODULE - DESCRIPTION Body Control Module) for more information on this component.
* Horn(s)
* Horn relay
* Horn switch

Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin-out information and location views for the various wire harness connectors, splices and grounds. Following are general descriptions of the remaining major components in the horn system.


Central Timer Module
The high-line or premium Central Timer Module (CTM) can also operate the horn system. A high-line CTM is used on high-line versions of this vehicle. A premium CTM is used on vehicles equipped with the optional heated seats. The CTM combines the functions of a chime/buzzer module, an intermittent wipe module, an illuminated entry module, a remote key-less entry module, and a vehicle theft security system module in a single unit.

The high-line or premium CTM also controls and integrates many of the additional electronic functions and features included on models with this option. The horn relay is one of the hard wired outputs of the CTM. The high-line or premium CTM is programmed to energize or de-energize the horn relay in response to certain inputs from the Vehicle Theft Security System (VTSS) and/or the Remote Keyless Entry (RKE) system. (Refer to BODY CONTROL/CENTRAL TIMER MODULE - DESCRIPTION Body Control Module) for more information on the high-line or premium CTM. (Refer to VEHICLE THEFT SECURITY - GENERAL INFORMATION Antitheft and Alarm Systems) for more information on the VTSS. (Refer to POWER LOCKS - GENERAL INFORMATION Keyless Entry) for more information on the RKE system.

When the horn is energized, electrical current flows through the closed contact points to the electromagnet. The resulting electromagnetic field draws the plunger and diaphragm toward it until that movement mechanically opens the contact points. When the contact points open, the electromagnetic field collapses allowing the plunger and diaphragm to return to their relaxed positions and closing the contact points again. This cycle continues repeating at a very rapid rate producing the vibration and movement of air that creates the sound that is directed through the horn outlet.