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Home >> Cadillac >> 2007 >> Escalade EXT >> Repair and Diagnosis >> External Pages >> Different car >> Section 1470 (Lighting System) >> Diagnostic Information and Procedures >> DTC B2645 >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2009 Saturn Vue. 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, scan tool OFF, doors CLOSED, test for less than 10 ohms between the appropriate ground circuit terminal listed below and ground.
    • Ground terminal B - with C67
    • Ground terminal C - with C68
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Ambient Light Sensor parameter is greater than 4.65 volts.
    • If less than the specified range, test the appropriate signal circuit terminal listed below for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
      • Signal terminal A - with C67
      • Signal terminal D - with C68
  4. Install a 3A fused jumper wire between the appropriate signal circuit terminal listed below and ground. Verify the scan tool Ambient Light Sensor parameter is less than 0.196 volts.
    • Signal terminal A - with C67
    • Signal terminal D - with C68
    • If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the ambient light sensor.