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Home >> GMC >> 2018 >> Acadia Denali, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 339 (Horn System) >> Diagnostic Information and Procedures >> Horns Malfunction >> Circuit/System Verification

Circuit/System Verification

WARNING: This page is about a different car, the 2017 GMC Acadia. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition » On / Vehicle » In Service Mode
  2. S33 Horn Switch»Not Pressed

    Verify the scan tool parameter:Horn Switch=Inactive

    • If not the specified state 

      Refer to: Circuit/System Testing - Test 1

    • If the specified state 
  3. Operate the component:S33 Horn Switch»Pressed

    Verify the scan tool parameter:Horn Switch=Active

    • If not the specified state 

      Refer to: Circuit/System Testing - Test 1

    • If the specified state 
  4. Perform the scan tool control function:Horn Relay Command »On and Off

    Verify the component turns On and Off:P12L Horn - Left & P12R Horn - Right & The horn should emit a clear and even tone.

    • If none of the components operate 

      Refer to: Circuit/System Testing - Test 2

    • P12 Horn - Inoperativeor If an abnormal noise is present 
    • Refer to: Circuit/System Testing - Test 3
    • If the component turns On and Off & If no abnormal noise is present 
  5. All OK.