Circuit/System Verification
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2012 GMC Yukon XL, 2012 GMC Yukon, 2012 Chevrolet Tahoe, 2012 Chevrolet Suburban, and 2012 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, connect a test lamp between the HORN fuse test point and ground.
- Press and release the horn switch. The test lamp should turn ON and OFF when changing between the commanded states.
- If the test lamp does not illuminate or remains illuminated at all times, refer to Horn Switch Circuit Test.
- Ignition ON, command the horn ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- If the test lamp does not illuminate, test the control circuit terminal 18 at the BCM for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
- Connect a 15 A fused jumper wire between B+ and the HORN fuse test point. The horns should sound and emit a clear and even tone.
- If the horn does not sound, refer to Horn Circuit Test.
- If the sound emitted is not clear and even, refer to Horn - Poor Tone.