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Home >> Cadillac >> 2012 >> Escalade EXT >> Repair and Diagnosis >> External Pages >> Different car >> Section 1087 (Lighting Systems) >> Diagnostic Information and Procedures >> DTC B2555 >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the appropriate front door courtesy lamp.
  2. Ignition OFF, scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 5.0 ohms between the low control circuit terminal B and ground.
    • If greater than the specified range, test the low control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the appropriate door control module.
  3. Connect a test lamp between the high control circuit terminal A and the low control circuit terminal B.
  4. Command the courtesy 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 high control circuit for a short to voltage. If the circuit tests normal, replace the appropriate door control module.
    • If the test lamp is always OFF, test the high control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the appropriate door control module.
  5. If all circuits test normal, test or replace the appropriate door courtesy lamp.
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