Circuit/System Testing
- Ignition OFF, disconnect the HORN relay.
- Connect a test lamp between the relay coil B+ circuit and the relay coil control circuit.
- Ignition ON, command the Horn ON and OFF with the scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
- If all circuits test normal, test or replace the HORN relay.