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Circuit/System Testing

WARNING: This page is about a different car, the 2021 Buick Enclave. However, it is still accessible from the selected car via links, so may be relevant.

Dimmer Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the S30 Headlamp Switch, ignition ON.
  2. Test for B+ between the B+ reference circuit terminal 12 and ground.
    • If less than B+ 
    1. Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module.
    2. Test for infinite resistance between the B+ reference circuit terminal 12 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 B+ reference 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.
    • Go to next step: If B+ 
  3. Verify a test lamp does not illuminate between B+ and the signal circuit terminal 11.
    • If the test lamp illuminates 
    1. Ignition OFF, disconnect the X2 harness connector at the K9 Body Control Module.
    2. Test for infinite resistance between the signal circuit terminal 11 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K9 Body Control Module.
    • Go to next step: If the test lamp does not illuminate 
  4. Test for B+ between the B+ reference circuit terminal 12 and the signal circuit terminal 11.
    • If less than B+ 
    1. Ignition OFF, disconnect the X2 harness connector at the K9 Body Control Module, ignition ON.
    2. Test for less than 1 V between the signal circuit terminal 11 and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    3. Test for less than 2 Ω in the signal 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.
    • Go to next step: If B+ 
  5. Test for B+ between the B+ reference circuit terminal 12 and the low reference circuit terminal 7.
    • If less than B+ 
    1. Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module, ignition ON.
    2. Test for less than 1 V between the low reference circuit terminal 7 and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    3. Test for less than 2 Ω in the low reference 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.
    • Go to next step: If B+ 
  6. Verify a test lamp does not illuminate between the B+ reference circuit terminal 12 and ground.
    • If the test lamp illuminates 
    1. Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module, ignition ON.
    2. Test for less than 1 V between the B+ reference circuit terminal 12 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 does not illuminate 
  7. Test or replace the S30 Headlamp Switch.

Interior Backlight Malfunction

    NOTE:

    Each component with backlight may need to be disconnected to isolate a short to voltage or short to ground. Use the schematics to identify the following:

    • Backlight components the vehicle is equipped with
    • Each component's control and ground circuit terminals
    • Component locations on the backlight control circuit
  1. Ignition OFF, scan tool disconnected, all doors closed, all accessories OFF, open and close drivers door, disconnect the harness connector at the component with inoperative backlight. 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 and ground.
    • If 10 Ω or greater 
    1. Ignition 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 and ground, ignition ON.
  4. Verify the test lamp turns ON and OFF when commanding the LED Backlight Dimming ON and OFF with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF, disconnect the appropriate harness connector listed below at the K9 Body Control Module.
      • X2 terminal 8
      • X7 terminal 9
    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, disconnect the appropriate harness connector listed below at the K9 Body Control Module, ignition ON.
      • X2 terminal 8
      • X7 terminal 9
    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 component with inoperative backlight.

Switch Indicator LED Backlight Malfunction

  1. Ignition OFF, disconnect the harness connectors at the components listed below.
    • S126 Drive Mode Select Switch (X88)
    • S26 Hazard Warning Switch (W49)
  2. Test for less than 10 Ω between the ground circuit terminal 3 and ground.
    • If 10 Ω or greater 
    1. Ignition 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 control circuit terminal 8 and ground, ignition ON.
  4. Verify the test lamp turns ON and OFF when commanding the Indicator Dimming ON and OFF with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF, disconnect the X1 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, disconnect the X1 harness connector at the K9 Body Control Module, ignition ON.
    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 inoperative component.

Dome Lamp Switch Indicator LED Backlight Malfunction

  1. Ignition OFF, disconnect the harness connector at the A98 Front Overhead Console. Ignition ON/Vehicle In Service Mode.
  2. Connect a test lamp between the control circuit terminal 18 and ground, ignition ON.
  3. Verify the test lamp turns ON and OFF when commanding the Indicator Dimming ON and OFF with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF, disconnect the X1 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, disconnect the X1 harness connector at the K9 Body Control Module, ignition ON.
    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 
  4. Ignition OFF, connect the A98 Front Overhead Console Assembly.
  5. Disconnect the X6 harness connector at the K9 Body Control Module. Ignition ON/Vehicle In Service Mode
  6. Verify the Dome Lamp Switch indicator is not illuminated.
    • If illuminated 
    1. Ignition OFF, disconnect the harness connector at the A98 Front Overhead Console Assembly.
    2. Test for infinite resistance between the control circuit terminal 11 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, test or replace the A98 Front Overhead Console Assembly.
    • Go to next step: If not illuminated 
  7. Ignition ON/Vehicle In Service Mode, connect a 3 A fused jumper wire between the control circuit terminal 11 and ground.
  8. Verify the Dome Lamp Switch indicator is illuminated.
    • If not illuminated 
    1. Ignition OFF/Vehicle OFF, remove the jumper wire, disconnect the harness connector at the A98 Front Overhead Console, ignition ON / Vehicle In Service Mode.
    2. Test for less than 1 V between the control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    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, test or replace the A98 Front Overhead Console.
    • Go to next step: If illuminated 
  9. Test or replace the K9 Body Control Module.
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