Circuit/System Testing
WARNING: This page is about a different car, the 2007 Saturn Sky. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, disconnect the appropriate harness connector at the ECM.
- Connect a test lamp between stop lamp switch signal circuit and ground.
- Ignition ON, apply the brake pedal ON and OFF. The test lamp should turn ON and OFF as the brake pedal is applied and released.
- If the test lamp is always ON, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
- If all circuits test normal, replace the ECM.