The horn is controlled by the horn relay through a low side drive control circuit. Battery voltage is supplied to the horn at all times from the underhood fuse block and when the relay is energized the horn control circuit is grounded through the relay. The horn relay is controlled by the horn switch through a low side drive control circuit. Battery voltage is supplied to the relay coil at all times and when the horn switch is pressed the relay control circuit is grounded and the relay will be energized.

Schematic Reference

Horn Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Horns System Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information.

1. Ignition OFF, disconnect the horn relay.
2. Test for less than 10 ohms between the ground circuit terminal 30 and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

3. Verify that a test lamp illuminates between the B+ circuit terminal 85 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the horn B+ circuit for a short to ground.

4. Disconnect the harness connector at the horn.
5. Verify that a test lamp illuminates between the B+ circuit terminal 2 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

6. Connect the harness connector at the horn.
7. Connect a 10 A fused jumper wire between the horn control circuit terminal 87 and the ground circuit terminal 30. Verify the horn is on.

⇒	If the horn does not activate, test the horn control circuit for an open/high resistance. If the circuit tests normal, test or replace the horn.

8. Connect a test lamp between the B+ circuit terminal 85 and the relay control circuit terminal 86.
9. Press and release the horn switch. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the horn switch.

⇒	If the test lamp is always OFF, test the control circuit for an open/high resistance. If the circuit tests normal, replace the horn switch.

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Horn Replacement