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Home >> GMC >> 2018 >> Acadia Denali, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 334 (Lighting System) >> Diagnostic Information and Procedures >> Trailer Lamps 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.
  2. Verify the vehicles park lamps turn ON and OFF when commanding the Park Lamps ON and OFF with a scan tool.
    • If the vehicles park lamps turn ON and OFF 
  3. Verify the vehicles backup lamps turn ON and OFF when commanding the Backup Lamps ON and OFF with a scan tool.
    • If the vehicles backup lamps turn ON and OFF 
  4. Verify the vehicles left brake lamp turns ON and OFF when commanding the Left Brake Lamp ON and OFF with a scan tool.
    • If the vehicles left brake lamp turns ON and OFF 
  5. Verify the vehicles right brake lamp turns ON and OFF when commanding the Right Brake Lamp ON and OFF with a scan tool.
    • If the vehicles right brake lamp turns ON and OFF 
  6. Verify the vehicles left and right turn signal lamps turn ON and OFF when commanding the left and right turn signal lamps ON and OFF with the turn signal/multifunction switch.
    • If the vehicles left and right turn signal lamps turn ON and OFF 
  7. Refer to Circuit/System Testing.