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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 >> Backup Lamps Malfunction (Automatic Transmission) >> Circuit/System Testing

Circuit/System Testing

Backup Lamps Malfunction (without T90)

  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, disconnect the X1 harness connector 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, disconnect the X1 harness connector 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, exterior lamps OFF, disconnect the harness connector at the appropriate E5 Backup Lamp. It may take up to 2 min for all vehicle systems to power down.
  5. Test for less than 5 Ω between the ground circuit terminal B and ground.
    • If 5 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 5 Ω 
  6. Connect a test lamp between the control circuit terminal A and ground, ignition ON.
  7. Verify the test lamp turns ON and OFF when commanding the Backup Lamps ON and OFF with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF, disconnect the X7 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 X7 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 
  8. Test or replace the E5 Backup Lamp.

Backup Lamp Malfunction (with T90)

  1. Ignition OFF, disconnect the X5 harness connector at the K9 Body Control Module, ignition ON.
    2. 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.

  2. Verify a test lamp illuminates between the control circuit terminal 20 and ground.
    • If the test lamp does not illuminate 
    1. Ignition OFF, disconnect the X2 harness connector at the X53A Fuse Block - Rear Body.
    2. Test for infinite resistance between the control circuit terminal 20 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 X53A Fuse Block - Rear Body.
    • Go to next step: If the test lamp illuminates 
  3. Ignition OFF, connect a 3 A fused jumper between the control circuit terminal 20 and ground.
  4. Remove the backup lamp fuse (F20RA) at the X53A Fuse Block - Rear Body, ignition ON.
  5. Verify a test lamp illuminates between the backup lamp fuse (F20RA) B+ switch control terminal and ground.
    • If the test lamp does not illuminate 
    1. Ignition OFF, disconnect the X2 harness connector at the X53A Fuse Block - Rear Body, ignition ON.
    2. Test for less than 1 V between the control circuit terminal 20 and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the X53A Fuse Block - Rear Body.
    • Go to next step: If the test lamp illuminates 
  6. Ignition OFF, connect the X5 harness connector at the K9 Body Control Module.
  7. Install the backup lamp fuse (F20RA) at the X53A Fuse Block - Rear Body.
  8. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the E83 Backup/Rear Fog Lamp. It may take up to 2 min for all vehicle systems to power down.
  9. Test for less than 5 Ω between the ground circuit terminal 1 and ground.
    • If 5 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 5 Ω 
  10. Connect a test lamp between the control circuit terminal 2 and ground, ignition ON.
  11. Verify the test lamp turns ON and OFF when commanding the Backup Lamps ON and OFF with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF, disconnect the X2 harness connector at the X53A Fuse Block - Rear Body.
    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 X2 harness connector at the X53A Fuse Block - Rear Body, 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 
  12. Test or replace the E83 Backup/Rear Fog Lamp.
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