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Circuit/System Testing

DTC B3950

  1. Ignition OFF, disconnect the X5 harness connector at the K9 body control module, ignition ON.
  2. Verify a test lamp illuminates between the B+ circuit terminal 4 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF.
    2. Test for less than 2Ω in the B+ circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω, verify the fuse is not open and there is voltage at the fuse.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition OFF.
    2. Test for infinite resistance between the B+ circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K9 body control module.
    • If the test lamp illuminates 
  3. Ignition OFF, connect the X5 harness connector at the K9 body control module.
  4. Ignition OFF, exterior lamps OFF, remove the E5AM stop/turn signal lamp bulb - left.
  5. Test for less than 5Ω between the ground circuit terminal 3 and ground.
    • If 5Ω or greater 
    1. Ignition OFF.
    2. Test for less than 2Ω in the ground circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω, repair the open/high resistance in the ground connection.
    • If less than 5Ω 
  6. Connect a test lamp between the control circuit terminal 2 and ground, ignition ON.
  7. Verify the test lamp turns ON and OFF when commanding the Left Rear Turn Signal/Brake Lamp ON and OFF with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF, disconnect the X5 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.
      • If infinite resistance
    3. Test for less than 2Ω in the control circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω, replace the K9 body control module.
    • If the test lamp is always ON 
    1. Ignition OFF, disconnect the X5 harness connector at the K9 body control module, ignition ON.
    2. Test for less than 1V between the control circuit terminal and ground.
      • If 1V or greater, repair the short to voltage on the circuit.
      • If less than 1V, replace the K9 body control module.
    • If the test lamp turns ON and OFF 
  8. Test or replace the E5AM stop/turn signal lamp bulb - left.

DTC B3951

  1. Ignition OFF, disconnect the X5 harness connector at the K9 body control module, ignition ON.
  2. Verify a test lamp illuminates between the B+ circuit terminal 3 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF.
    2. Test for less than 2Ω in the B+ circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω, verify the fuse is not open and there is voltage at the fuse.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition OFF.
    2. Test for infinite resistance between the B+ circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K9 body control module.
    • If the test lamp illuminates 
  3. Ignition OFF, connect the X5 harness connector at the K9 body control module.
  4. Ignition OFF, exterior lamps OFF, remove the E5AN stop/turn signal lamp bulb - right.
  5. Test for less than 5Ω between the ground circuit terminal 3 and ground.
    • If 5Ω or greater 
    1. Ignition OFF.
    2. Test for less than 2Ω in the ground circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω, repair the open/high resistance in the ground connection.
    • If less than 5Ω 
  6. Connect a test lamp between the control circuit terminal 2 and ground, ignition ON.
  7. Verify the test lamp turns ON and OFF when commanding the Right Rear Turn Signal/Brake Lamp ON and OFF with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF, disconnect the X4 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.
      • If infinite resistance
    3. Test for less than 2Ω in the control circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω, replace the K9 body control module.
    • If the test lamp is always ON 
    1. Ignition OFF, disconnect the X4 harness connector at the K9 body control module, ignition ON.
    2. Test for less than 1V between the control circuit terminal and ground.
      • If 1V or greater, repair the short to voltage on the circuit.
      • If less than 1V, replace the K9 body control module.
    • If the test lamp turns ON and OFF 
  8. Test or replace the E5AN stop/turn signal lamp bulb - right.
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