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Home › Chevrolet › 2006 › Impala SS › Repair and Diagnosis › External Pages › Different car › Section 439 (Lighting System) › Diagnostic Information and Procedures › DTC B2645 › Circuit/System Testing

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.
  1. Ignition OFF, disconnect the harness connector at the ambient light sensor.
  2. Ignition OFF, test for less than 1 ohm of resistance between the low reference circuit terminal B and ground.
    • If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the BCM.
  3. Ignition ON, verify the scan tool ambient light sensor parameter is between 1-5 volts.
    • If less than the specified range, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the BCM.
    • If greater than the specified range, test the signal circuit terminal A for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. If all circuits test normal, replace the ambient light sensor.
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