Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

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 body control module (BCM) 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.

The BCM monitors the voltage level on the horn relay control circuit whenever the ignition is in the RUN position.

The BCM will set DTC B2752 as current whenever an improper voltage level is detected on the horn relay control circuit for more than 15 seconds.

The BCM will disable the driver for the horn relay control circuit whenever DTC B2752 is set as current.

DTC B2752 will clear when an improper voltage level is no long detected on the horn relay control circuit, or when a scan tool is used to clear DTCs.

Inspect for a sticking horn pad or horn switch.

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 BCM Horn Output. The horn relay should click and the horn should sound while commanded ON and stop sounding when commanded OFF.

1. Ignition ON, install a scan tool.
2. Remove the horn relay.
3. Connect a test lamp between the battery supply voltage circuit and the horn relay control circuit.
4. 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 turn signal/multifunction switch and the horn switch. If the circuit/connections test normal, replace the BCM.

⇒	If the test lamp remains illuminated at all times, test the horn relay circuit for a short to ground. The horn relay control circuit includes the turn signal/multifunction switch and the horn switch. If the circuit/connections test normal, replace the BCM.

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

Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.