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Circuit/System Testing

Front Fog Lamp Switch Malfunction

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the S30 Headlamp switch, ignition ON.
  2. Test for B+ between the B+ circuit terminal 1 and ground.
    • If less than B+ 
    1. Ignition OFF, disconnect the X3 harness connector at the K9 body control module.
    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
    3. 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, replace the K9 body control module.
    • If B+ 
  3. Verify the scan tool LED Backlight Dimming Command parameter is greater than 40%.
    • If 40% or less 
    1. Ignition OFF, disconnect the X1 harness connector at the K9 body control module, ignition ON.
    2. Test for less than 1V between the signal circuit terminal 12 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 greater than 40% 
  4. Install a 3A fused jumper wire between the signal circuit terminal 12 and the B+ circuit terminal 1.
  5. Verify the scan tool LED Backlight Dimming Command parameter is less than 30%.
    • If 30% or greater 
    1. Ignition OFF, disconnect the X1 harness connector at the K9 body control module.
    2. Test for infinite resistance between the signal 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 signal 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 less than 30% 
  6. Test or replace the S30 Headlamp switch.

Front Fog Lamps Malfunction

  1. Ignition OFF, disconnect the X2 harness connector at the X50A Fuse block - underhood.
  2. Connect a test lamp between the control circuit terminal 19 and B+, ignition ON.
  3. Verify the test lamp turns ON and OFF when commanding the Front Fog Lamps 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, 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
    3. Ignition OFF.
    4. 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.
    2. Test for infinite resistance between the control circuit terminal 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 turns ON and OFF 
  4. Ignition OFF, connect the X2 harness connector at the X50A Fuse block - underhood.
  5. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the appropriate E29 fog lamp.
  6. Test for less than 5Ω between the ground circuit terminal 2 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 
  7. Connect a test lamp between the control circuit terminal 1 and ground, ignition ON.
  8. Verify the test lamp turns ON and OFF when commanding the Front Fog Lamps ON and OFF with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF, disconnect the X1 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.
      • 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 X50A Fuse block - underhood.
    • If the test lamp is always ON 
    1. Ignition OFF, disconnect the X1 harness connector at the X50A Fuse block - underhood, 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 X50A Fuse block - underhood.
    • If the test lamp turns ON and OFF 
  9. Test or replace the appropriate E29 fog lamp.

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.

    • If the front fog lamp indicator turns ON and OFF 
  3. Replace the K9 body control module.
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