Horn: Description and Operation

HORN SYSTEM
DESCRIPTION
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
- High-line Central Timer Module (CTM)
- Horn(s)
- Horn relay
- Horn switch

Refer to Clockspring in the Description and Operation of Passive Restraint Systems for more information on this component. Refer to Central Timer Module in the Description and Operation of Instrument Panel Systems for more information on this component.

OPERATION
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).

Refer to the owner's manual in the vehicle glove box for more information on the features, use and operation of the horn system.

HORN
DESCRIPTION
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.

OPERATION
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.

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.