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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.

Stop Lamps Malfunction

  1. Ignition OFF, disconnect harness connector at the inoperative stop lamp.
  2. Test for less than 1.0 ohm of resistance between the ground circuit and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the stop lamp supply voltage circuit and ground.
  4. Command the inoperative stop lamp 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 is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
    • If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, replace the inoperative stop lamp.

High Mounted Stop Lamp Malfunction

  1. Ignition OFF, disconnect the harness connector at the CHMSL.
  2. Test for less than 1.0 ohm of resistance between the ground circuit terminal B and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the stop lamp switch signal circuit terminal A and ground circuit terminal B.
  4. 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 OFF, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
    • If the test lamp is always ON, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, replace the CHMSL.
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