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Home >> Cadillac >> 2021 >> CT4 Sport, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 224 (Lighting System - Diagnostic Information And Procedures (1 Of 2)) >> Diagnostic Information and Procedures >> DTC B1994 or B1995 >> Circuit/System Testing

Circuit/System Testing

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DTC B1995

  1. Ignition OFF, exterior lamps OFF, disconnect the connector at the E13LA Front Headlamp - Left.
  2. Connect a test lamp between control circuit terminal 3 and ground circuit terminal 1.
  3. Ignition ON, verify the test lamp turns ON and OFF when commanding the Left High Beam Command ON and OFF with a scan tool.
    • If the test lamp is always ON 
    1. Test circuit 711 for a short to voltage
      • If a short to voltage is found, repair the fault.
      • Go to next step: If a short to voltage is not found, replace the K219 Lighting Control Module.
    • If the test lamp is always OFF 
    1. Test circuit 550 for an open/high resistance
      • If an open/high resistance is found, repair the fault on the circuit or ground connection.
      • Go to next step: If an open/high resistance is not found
    2. Test circuit 711 for an open/high resistance
      • If an open/high resistance is found, repair the fault on the circuit
      • Go to next step: If an open/high resistance is not found
    3. Test circuit 711 for short to ground
      • If a short to ground is found, repair the fault on the circuit
      • Go to next step: If a short to ground is not found
    4. Replace the K219 Lighting Control Module.
    • Go to next step: If the test lamp turns ON and OFF 
  4. Replace the E13LA Front Headlamp - Left.

DTC B1994

  1. Ignition OFF, exterior lamps OFF, disconnect the connector at the E13RA Front Headlamp - Right.
  2. Connect a test lamp between control circuit terminal 3 and ground circuit terminal 1.
  3. Ignition ON, verify the test lamp turns ON and OFF when commanding the Right High Beam Command ON and OFF with a scan tool.
    • If the test lamp is always ON 
    1. Test circuit 311 for a short to voltage
      • If a short to voltage is found, repair the fault.
      • Go to next step: If a short to voltage is not found, replace the K219 Lighting Control Module.
    • If the test lamp is always OFF 
    1. Test circuit 650 for an open/high resistance
      • If an open/high resistance is found, repair the fault on the circuit or ground connection.
      • Go to next step: If an open/high resistance is not found
    2. Test circuit 311 for an open/high resistance
      • If an open/high resistance is found, repair the fault on the circuit
      • Go to next step: If an open/high resistance is not found
    3. Test circuit 311 for short to ground
      • If a short to ground is found, repair the fault on the circuit
      • Go to next step: If a short to ground is not found
    4. Replace the K219 Lighting Control Module.
    • Go to next step: If the test lamp turns ON and OFF 
  4. Replace the E13RA Front Headlamp - Right.
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