Circuit/System Testing
- Ignition ON, install a scan tool.
- Remove the horn relay.
- Connect a test lamp between the battery supply voltage circuit and the horn relay control circuit.
- Verify the test lamp turns ON and OFF when using the scan tool to command the horn relay.
- If the test fails to illuminate, test the horn relay control circuit for a short to voltage or an open. The horn relay control circuit includes the steering wheel coil assembly and horn switch. If the circuit/connections test normal, replace the BCM.
- If the test lamp remains illuminated at all times, test the horn relay control circuit for a short to ground. The horn relay control circuit includes the steering wheel coil assembly and horn switch. If the circuit/connections test normal, replace the BCM.
- If all circuits test normal, test or replace the horn relay.