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Home >> Cadillac >> 2018 >> XT5 Platinum >> Repair and Diagnosis >> Accessories & Equipment >> Headlights >> Lighting System - Diagnostic Information And Procedures (DTC B3950 - C0297) >> Diagnostic Information and Procedures >> Exterior Courtesy Lamps Malfunction >> Circuit/System Testing

Circuit/System Testing

    NOTE:

    Each component may need to be disconnected to isolate a short to voltage, short to ground, or an open/high resistance. Use the wiring schematics to identify the following:

    • Exterior courtesy lamps the vehicle is equipped with
    • Each component's control and ground circuit terminals
    • Component locations on the exterior courtesy lamps control circuit
  1. Ignition OFF/Vehicle OFF, scan tool disconnected, all doors closed, all accessories OFF, open and close drivers door, disconnect the harness connector at the inoperative exterior courtesy lamp. It may take up to 2 min for all vehicle systems to power down.
  2. Test for less than 10 Ω between the appropriate ground circuit terminal listed below and ground.
    • A24D Door Handle Assembly - Driver Exterior terminal 4
    • A24P Door Handle Assembly - Passenger Exterior terminal 4
    • A24LR Door Handle Assembly - Left Rear Exterior terminal 4
    • A24RR Door Handle Assembly - Right Rear Exterior terminal 4
    • If 10 Ω or greater 
    1. Ignition OFF/Vehicle OFF.
    2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • Go to next step: If less than 10 Ω 
  3. Connect a test lamp between the appropriate control circuit terminal listed below and ground, ignition ON/vehicle in Service Mode.
    • A24D Door Handle Assembly - Driver Exterior terminal 5
    • A24P Door Handle Assembly - Passenger Exterior terminal 5
    • A24LR Door Handle Assembly - Left Rear Exterior terminal 5
    • A24RR Door Handle Assembly - Right Rear Exterior terminal 5
  4. Verify the test lamp turns ON and OFF when commanding the Outside Rear View Mirror Courtesy Lamp ON and OFF with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF/Vehicle OFF, disconnect the X3 harness connector at the K9 Body Control Module.
    2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    3. Test for less than 2 Ω in the control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K9 Body Control Module.
    • If the test lamp is always ON 
    1. Ignition OFF/Vehicle OFF, disconnect the X3 harness connector at the K9 Body Control Module, ignition ON/vehicle in Service Mode.
    2. Test for less than 1 V between the control circuit terminal and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K9 Body Control Module.
    • Go to next step: If the test lamp turns ON and OFF 
  5. Test or replace the courtesy lamp.