LEMON Manuals: Even more car manuals for everyone
Home >> Buick >> 2018 >> Regal GS >> Repair and Diagnosis >> Accessories & Equipment >> Exterior Lights >> Lighting System - Diagnostic Information And Procedures (B388B-P0504) And Symptoms >> Diagnostic Information and Procedures >> Front Fog Lamps Malfunction >> Circuit/System Testing

Circuit/System Testing

Front Fog Lamp Switch Malfunction

  1. Ignition OFF, scan tool disconnected, all doors closed, all accessories OFF, disconnect the harness connector at the S30 Headlamp Switch. 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 8 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. Ignition ON.
  4. Verify the scan tool Front Fog Lamps Relay Command parameter is Inactive.
    • If not Inactive 
    1. Ignition OFF, disconnect the X3 harness connector at the K9 Body Control Module.
    2. Test for infinite resistance between the signal circuit terminal 10 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 Inactive 
  5. Install a 3 A fused jumper wire between the signal circuit terminal 10 and ground.
  6. Verify the scan tool Front Fog Lamps Switch parameter is Active.
    • If not Active 
    1. Ignition OFF, disconnect the X3 harness connector at the K9 Body Control Module, ignition ON.
    2. Test for less than 1 V between the signal circuit terminal 10 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 Active 
  7. Test or replace the S30 Headlamp Switch.

Front Fog Lamps Malfunction

  1. Ignition OFF, exterior lamps OFF, remove the appropriate E29 Fog Lamp - Front. 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 1 and ground, ignition ON.
  4. Verify the test lamp does not turn ON and OFF when commanding the Front Fog Lamps ON and OFF with a scan tool.
    • If the test lamp turns ON and OFF 

      Test or replace the E29 Fog Lamp - Front.

    • Go to next step: If the test lamp does not turn ON and OFF 
  5. Ignition OFF, install the E29 Fog Lamp - Front. Disconnect the X2 harness connector at the X50A Fuse Block - Underhood, ignition ON.
  6. Verify the front fog lamps do not illuminate.
    • If the front fog lamps illuminate 
    1. Ignition OFF, remove both E29 Fog Lamp - Front, ignition ON.
    2. Test for less than 1 V between the control circuit terminal C1 and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
    • Go to next step: If the front fog lamps do not illuminate 
  7. Ignition OFF, connect a 3 A fused jumper between the control circuit terminal C1 and B+, ignition ON.
  8. Verify the front fog lamps illuminate.
    • If the front fog lamps do not illuminate 
    1. Ignition OFF, remove the 3 A fused jumper wire, remove both E29 Fog Lamp - Front.
    2. Test for infinite resistance between the control circuit terminal C1 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, all OK.
    • Go to next step: If the front fog lamps illuminate 
  9. Ignition OFF, connect the X2 harness connector at the X50A Fuse Block - Underhood.
  10. Disconnect the X5 harness connector at the K9 Body Control Module, ignition ON.
    11. 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.

  11. 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 X50A Fuse Block - Underhood.
    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 X50A Fuse Block - Underhood.
    • Go to next step: If the test lamp illuminates 
  12. Ignition OFF, connect a 3 A fused jumper between the control circuit terminal 20 and ground, ignition ON.
  13. Verify both E29 Fog Lamp - Front illuminate.
    • If the front fog lamps do not illuminate 
    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 20 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 front fog lamps illuminate 
  14. Test or replace the K9 Body Control Module.

Front Fog Lamp Indicator Malfunction

  1. Ignition ON.
  2. Verify the front fog lamp indicator turns ON and OFF when commanding the Instrument Cluster All Indicators Test ON and OFF with a scan tool.
    • If the front fog lamp indicator is always OFF or remains ON 

      Replace the P16 Instrument Cluster.

    • Go to next step: If the front fog lamp indicator turns ON and OFF 
  3. Replace the K9 Body Control Module.
scientia non olet · About LEMON Manuals