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 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.

Schematic Reference

Horn Schematics

Connector End View Reference

Horn Connector End Views

Electrical Information Reference

Scan Tool Reference

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.

1. Ignition OFF, remove the horn relay. The horn should stop sounding with the relay removed.

⇒	If the horn continues to sound, repair the short to voltage on the horn control circuit.

2. Verify that a test lamp does not illuminate when connected between the horn relay supply voltage circuit and the horn relay control circuit.

⇒	If the test lamp illuminates, test for a short to ground on the horn relay control circuit. The horn relay control circuit includes the steering wheel coil assembly and horn switch. If the circuit/connections test normal, replace the instrument panel module (IPM).

3. If all circuits test normal, test or replace the horn relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.