Horns - Poor Tone

Horns - Poor Tone

Diagnostic Fault Information

Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview

Circuit/System Description

Battery positive voltage is applied at all times to the horn relay coil and horn relay switch. Pressing the horn switch applies ground to the horn relay control circuit. The instrument panel module (IPM) also may apply ground to the horn relay control circuit. When the horn relay control circuit is grounded, the horn relay is energized and battery positive voltage is applied to the horn via the horn control circuit. The horn will sound as long as ground is applied to the horn relay control circuit.

Diagnostic Aids

Inspect for any debris or water in the horn assembly. Test the horn mounting hardware for proper torque. Refer to Fastener Tightening Specifications. Inspect for debris in the joint where the horns attach to the vehicle.

Circuit/System Verification

1. Press the horn switch. The horn relay should click and the horn should sound as long as the horn switch is pressed.
2. Turn ON the ignition. With a scan tool, command the IPM Horn Output. The horn relay should click and the horn should sound while commanded ON and stop sounding when commanded OFF.

Circuit/System Testing

1. Ignition OFF, remove the horn assembly.
2. Test for a high resistance on the horn control circuit.
3. If all circuits test normal, test or replace the horn assembly.

Component Testing

Using a 15-amp fused jumper, connect the horn to battery positive voltage and ground. The horn should emit a clear and even tone.

If the sound emitted is not clear and even, test or replace the horn assembly.

Repair Instructions

Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

Horn Replacement