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Home >> Chevrolet >> 2020 >> Camaro SS, 2D Coupe, Automatic Trans >> Repair and Diagnosis >> Accessories & Equipment >> Headlights >> Lighting System - Diagnostic Information And Procedures (B3950-C0297) And Symptoms >> Diagnostic Information and Procedures >> Interior Backlighting Malfunction >> Circuit/System Testing

Circuit/System Testing

Dimmer Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the S36 Instrument Panel Dimmer Switch, ignition ON.
  2. Test for B+ between the B+ reference circuit terminal 6 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 6 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 2.
    • 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 2 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 6 and the signal circuit terminal 2.
    • 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 2 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 6 and the low reference circuit terminal 1.
    • 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 1 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 6 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 6 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 S36 Instrument Panel Dimmer Switch.

Interior Backlighting Malfunction

    NOTE:

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

    • Backlighting components the vehicle is equipped with
    • Each component's control and ground circuit terminals
    • Component locations on the backlighting control circuit
  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, remove the F21UA fuse at the X50A Fuse Block - Underhood.
    2. Test for less than 2 Ω in the B+ circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, 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, remove the F21UA fuse at the X50A Fuse Block - Underhood.
    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.
    • Go to next step: If the test lamp illuminates 
  3. Ignition OFF, connect the X5 harness connector at the K9 Body Control Module.
  4. 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 backlighting. It may take up to 2 min for all vehicle systems to power down.
  5. 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 
  6. Connect a test lamp between the appropriate control circuit terminal and ground, ignition ON.
  7. 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 
  8. Test or replace the component with inoperative backlighting.

Switch Indicator LED Backlighting Malfunction

  1. Ignition OFF, disconnect the harness connectors at the components listed below.
    • S13D Door Lock Switch - Driver
    • S13P Door Lock Switch - Passenger
    • S70L Steering Wheel Controls Switch - Left
  2. Ignition ON, place the S36 Instrument Panel Dimmer Switch in the HIGH position for high backlighting intensity.
    3. NOTE:

    The test lamp in the following step will illuminate at LOW intensity. This is normal circuit operation and does not indicate a circuit malfunction.

  3. Verify a test lamp illuminates between each control circuit terminal listed below and ground.
    • S13D Door Lock Switch - Driver terminal 5
    • S13P Door Lock Switch - Passenger terminal 5
    • S70L Steering Wheel Controls Switch - Left terminal 7
    • If the test lamp does not illuminate 
    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.
    • Go to next step: If the test lamp illuminates 
  4. Place the S36 Instrument Panel Dimmer Switch in the LOW position for low backlighting intensity.
  5. Verify a test lamp does not illuminate at FULL intensity between each control circuit terminal listed below and ground.
    • S13D Door Lock Switch - Driver terminal 5
    • S13P Door Lock Switch - Passenger terminal 5
    • S70L Steering Wheel Controls Switch - Left terminal 7
    • If the test lamp illuminates at full intensity 
    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 does not illuminate at full intensity 
  6. Test or replace the appropriate component.

Passenger Air Bag Disable Indicator Backlighting Malfunction

  1. Ignition OFF, scan tool disconnected, all doors closed, all accessories OFF, open and close drivers door, disconnect the harness connector at the P14 Passenger Air Bag Disable Indicator. It may take up to 2 min for all vehicle systems to power down.
  2. Test for less than 10 Ω between the ground circuit terminal 2 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 4 and ground.
  4. Verify the test lamp turns ON and OFF while turning the ignition switch ON and OFF.
    • If the test lamp is always OFF 
    1. Ignition OFF, disconnect the X2 harness connector at the X50A Fuse Block - Underhood.
    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 X50A Fuse Block - Underhood.
    • If the test lamp is always ON 
    1. Ignition OFF, disconnect the X2 harness connector at the X50A Fuse Block - Underhood, 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 X50A Fuse Block - Underhood.
    • Go to next step: If the test lamp turns ON and OFF 
  5. Test or replace the P14 Passenger Air Bag Disable Indicator.
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