Horns Always on

HORNS ALWAYS ON

Diagnostic Fault Information




Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview

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.

2. IMPORTANT: The inflatable restraint steering wheel module coil and the horn switch are located under the inflatable restraint steering wheel module. To disable the SIR system refer to SIR Disabling and Enabling.

Ignition OFF, disconnect the C1 harness connector at the inflatable restraint steering wheel module coil.

3. Verify that a test lamp illuminates between the horn relay side of the HORN Fuse and ground.
- If the test lamp does not illuminate, replace the horn switch.

4. Disconnect the C5 harness connector at the body control module.
5. Verify that a test lamp illuminates between the horn relay side of the HORN Fuse and ground.
- If the test lamp turns OFF, replace the body control module.
- If the test lamp remains ON, test the horn relay control circuit for a short to ground. If all circuits test normal, replace the underhood fuse block.

Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
- Horn Switch Replacement
- Underhood Electrical Center or Junction Block Replacement
- Control Module References for the body control module replacement, setup, and programming Programming and Relearning