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Home >> Isuzu >> 2007 >> i-290 LS, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 37 (Horn System) >> Diagnostic Information and Procedures >> Horns Malfunction >> Circuit/System Verification

Circuit/System Verification

WARNING: This page is about a different car, the 2007 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.
  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 does not illuminate or remains illuminated at all times, 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 for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Connect a 15A fused jumper wire between the horn fused test point and B+. The horn 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.
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