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Home >> Cadillac >> 2009 >> Escalade EXT >> Repair and Diagnosis >> External Pages >> Different car >> Section 99 (Lighting Systems) >> Diagnostic Information & Procedures >> DTC B3884 >> Circuit/System Testing
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Circuit/System Testing

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  1. Ignition OFF, disconnect the harness connector at the center high mounted stop lamp.
  2. Test for less than 5.0 ohms 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 control circuit terminal A and ground circuit terminal B.
  4. Ignition ON, press and release the brake pedal. 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, test or replace the center high mounted stop lamp.
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