Horns Always On

Horns Always On

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information






Circuit/System Description

When the horn button is pressed, ground is applied through the horn switch contacts and the horn relay control circuit to the coil side of the relay. The horn relay coil is then energized, causing the relay switch contacts to close applying voltage through the horn fuse and the horn control circuit to the horns. For theft deterrent functions, the body control module (BCM) also controls the horn relay by applying ground to the relay control circuit to the relay.

Circuit/System Testing

1. Remove the HORN fuse from the underhood fuse block. The horns should turn OFF.

• If the horns remain ON, repair the short to voltage on the horn control circuit.

Important: The horn switch is located under the inflatable restraint steering wheel module. To disable the SIR system refer to SIR Service Precautions.

2. Ignition OFF, disconnect the inline harness connector C202.
3. Connect a test lamp between the horn relay side of the HORN fuse and ground. The test lamp should illuminate.

• If the test lamp does not illuminate, replace the horn switch.

4. Disconnect the C5 harness connector at the body control module.

• If the test lamp turns OFF, replace the body control module.

• If the test lamp remains ON, test for a short to ground on the horn relay control circuit. If all circuits test normal, replace the horn relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* Inflatable Restraint Steering Wheel Module Replacement
* Relay Replacement (Within an Electrical Center)
* Control Module References for BCM replacement, setup, and programming. Programming and Relearning