Horn: Description and Operation

INTRODUCTION

WARNING: ON VEHICLES EQUIPPED WITH AIRBAG, SEE AIR BAGS AND SEAT BELTS/AIR BAG, FOR STEERING WHEEL OR COLUMN REMOVAL PROCEDURES.

The horn circuit consists of a horn contact, horn relay, and horns. The horn circuit feed is from the fuse to the horn relay in the Junction Block. When the horn contact is depressed, it completes the ground circuit. Then the horn relay coil closes a set of contacts which allows current to flow to the horns. The horn(s) are grounded at the shock tower.

CIRCUIT OPERATION
The horn system is powered by a 20 Amp fuse located in cavity 8 of the junction block. The fuse is HOT at all times on circuit F30. This circuit supplies voltage to the coil and to the contact side of the horn relay Circuit F30 is spliced internal to the junction block and supplies voltage to the cigar lighter/power outlet and the power amplifier.

Power for the fuse is supplied on circuit A13 which originates in the Power Distribution Center (PDC) and is protected by a 40 Amp fuse located in cavity 14.

When the operator presses the horn switch, a ground path is completed on the coil side of the horn relay through the switch, on circuit X3. The horn relay, located in the junction block, then CLOSES the relay contacts. Voltage is passed through the CLOSED relay contacts on circuit X2 to the horns. Grounding for the horns is on the Z1 circuit.

On vehicles equipped with Vehicle Theft Security System (VTSS), the X3 circuit is spliced to the Body Control Module (BCM)

When the Vehicle Theft Security System (VTSS) is activated the Body Control Module (BCM) controls the operation of the horns and exterior lamps. To control the horns the BCM provides a ground for the X3 circuit. This circuit is spliced with the horn switch and Remote Keyless Entry (RKE) module and connects to the coil side of the horn relay.