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Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> External Pages >> Different car >> Section 468 (Horn System) >> Diagnostic Information and Procedures >> Horns Malfunction (with VD1) >> Circuit/System Verification

Circuit/System Verification

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  1. Ignition OFF, connect a test lamp between the HORN fuse test point and ground.
  2. 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 or always OFF, refer to Horn Switch Circuit Test.
  3. 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 harness connector X5 for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Connect a 15 A fused jumper wire between the HORN fuse test point and B+. The right horns should sound and emit a clear and even tone.
    • If the horns do not sound, refer to Right Horn Circuit Test.
    • If the sound emitted is not clear and even, refer to Right Horn - Poor Tone.
  5. Connect a 20 A fused jumper wire between the HDLMP WASH fuse test point and B+. The left horn should sound and emit a clear and even tone.
    • If the left horn does not sound, refer to Left Horn Circuit Test.
    • If the sound emitted is not clear and even, refer to Left Horn - Poor Tone.
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