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Circuit/System Testing

Diagnostic A

  1. Ignition OFF and all vehicle systems OFF, disconnect the KR73 Ignition Main Relay. 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.
    • If less than 10 Ω 
  3. Ignition ON.
  4. Verify a test lamp illuminates between the B+ circuit terminal 3 and ground.
    • If the test lamp does not illuminate 

      Replace the X50A Fuse Block - Underhood

    • If the test lamp illuminates 
  5. Connect a test lamp between the control circuit terminal 1 and the ground circuit terminal 2.
  6. Verify the test lamp turns ON and OFF when commanding the Run/Crank Relay On and Off with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF, remove the test lamp, disconnect the 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.
      • 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, remove the test lamp, disconnect the harness connector at the K9 Body Control Module, ignition ON.
    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.
      • If less than 1 V, replace the K9 Body Control Module.
    • If the test lamp turns ON and OFF 
  7. Verify that a test lamp does not illuminate between the ignition circuits listed below and ground.
    • Ignition circuit terminal 4
    • Ignition circuit terminal 5
    • If the test lamp illuminates 

      Repair the short to voltage on the ignition circuit.

    • If the test lamp does not illuminate 
  8. Ignition ON, connect a 40 A fused jumper wire between the B+ circuit terminal 3 and the ignition circuits listed below.
    • Ignition circuit terminal 4
    • Ignition circuit terminal 5
  9. Verify the appropriate device is activated.
    • If the device does not activate 
    1. Ignition OFF, disconnect the harness connector at the device.
    2. Test for infinite resistance between the ignition circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the ignition circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the device.
    • If the device activates 
  10. Test or replace the KR73 Ignition Main Relay.

Diagnostic B

  1. Ignition OFF and all vehicle systems OFF, disconnect the KR148 Steering Wheel Heater Relay. 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 1 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.
    • If less than 10 Ω 
  3. Ignition ON.
  4. Verify a test lamp illuminates between the B+ circuit terminal 5 and ground.
    • If the test lamp does not illuminate 

      Replace the X53A Fuse Block - Rear Body

    • If the test lamp illuminates 
  5. Connect a test lamp between the control circuit terminal 2 and the ground circuit terminal 1.
  6. Verify the test lamp turns ON and OFF when switching the ignition between ON and OFF.
    • If the test lamp is always OFF 
    1. Ignition OFF, remove the test lamp, disconnect the 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.
      • 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, remove the test lamp, disconnect the harness connector at the K9 Body Control Module, ignition ON.
    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.
      • If less than 1 V, replace the K9 Body Control Module.
    • If the test lamp turns ON and OFF 
  7. Verify that a test lamp does not illuminate between the ignition circuit terminal 3 and ground.
    • If the test lamp illuminates 

      Repair the short to voltage on the ignition circuit

    • If the test lamp does not illuminate 
  8. Ignition ON, connect a 10 A fused jumper wire between the B+ circuit terminal 5 and the ignition control circuit terminal 3.
  9. Verify device is activated.
    • If the device is not activated 
    1. Ignition OFF, disconnect the harness connector at the device.
    2. Test for infinite resistance between the ignition circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the ignition circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the device.
    • If the device activates 
  10. Test or replace the KR148 Steering Wheel Heater Relay.

Diagnostic C

  1. Ignition OFF and all vehicle systems OFF, disconnect the X81 Accessory Power Receptacle - 110V AC and P2 Transmission Shift Lever Position Indicator.
  2. Connect a test lamp between the ignition circuits listed below and ground.
      NOTE:

      The vehicle may not be equipped with all components as listed below. Use schematics to determine which devices are controlled directly by the K84 Keyless Entry Control Module's ignition circuit terminal 7 X1. Use the connector end view to identify the ignition circuit terminal for each of those devices.

    • P2 Transmission Shift Lever Position Indicator - Control circuit terminal 4
    • X81 Accessory Power Receptacle - 110V AC - Control circuit terminal 1 X1
    • X51A Fuse Block - Instrument Panel - Fuse F4DA
    • X51A Fuse Block - Instrument Panel - Fuse F30DA
    • X51A Fuse Block - Instrument Panel - Circuit Breaker F8DA
  3. Verify the test lamp turns ON and OFF when cycling the ignition between ON and OFF.
    • If the test lamp is always OFF 
    1. Ignition OFF, remove test lamp, disconnect the harness connector at the K84 Keyless Entry Control Module and X51A Fuse Block - Instrument Panel.
    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 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.
    4. Replace the K84 Keyless Entry Control Module.
    5. Connect the harness connector at the X51A Fuse Block - Instrument Panel.
    6. Verify the test lamp turns ON and OFF when cycling the ignition between ON and OFF.
      • If the test lamp is always OFF, replace the X51A Fuse Block - Instrument Panel.
      • If the test lamp turns ON and OFF.
    7. All OK.
    • If the test lamp is always ON 
    1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K84 Keyless Entry Control Module, ignition ON.
    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.
      • If less than 1 V, replace the K84 Keyless Entry Control Module.
    • If the test lamp turns ON and OFF 
  4. Disconnect the harness connector at the appropriate X80 Accessory Power Receptacle and X92 USB Receptacle.
  5. Ignition OFF.
  6. Verify that a test lamp does not illuminate between each of the ignition circuits listed below and ground.
    • X92 USB Receptacle - Ignition circuit terminal
    • X80L Accessory Power Receptacle - Center Console - Ignition circuit terminal
    • X80F Accessory Power Receptacle - Front - Ignition circuit terminal
    • X8H Accessory Power Receptacle - Center Console - Ignition circuit terminal
    • If the test lamp illuminates 

      Repair the short to voltage on the ignition circuit.

    • If the test lamp does not illuminate 
  7. Ignition ON.
  8. Verify that a test lamp illuminates between each of the ignition circuits listed below and ground.
    • X92 USB Receptacle - Ignition circuit terminal
    • X80L Accessory Power Receptacle - Center Console - Ignition circuit terminal
    • X80F Accessory Power Receptacle - Front - Ignition circuit terminal
    • X8H Accessory Power Receptacle - Center Console - Ignition circuit terminal
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF, remove the test lamp.
    2. Test for less than 2 Ω in the ignition 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 X51A Fuse Block - Instrument Panel.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition OFF.
    2. Test for infinite resistance between the ignition circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, test or replace the appropriate X80 Accessory Power Receptacle or X92 USB Receptacle.
    • If the test lamp illuminates 
  9. Test or replace the appropriate X80 Accessory Power Receptacle or X92 USB Receptacle.

Diagnostic D

  1. Ignition OFF and all vehicle systems OFF, disconnect the KR75 Engine Controls Ignition Relay, ignition ON.
  2. Verify a test lamp illuminates between the B+ circuit terminal 1 and ground.
    • If the test lamp does not illuminate 

      Replace the X50A Fuse Block - Underhood

    • If the test lamp illuminates 
  3. Verify a test lamp illuminates between the B+ circuit terminal 3 and ground.
    • If the test lamp does not illuminate 

      Replace the X50A Fuse Block - Underhood

    • If the test lamp illuminates 
  4. Connect a test lamp between the B+ circuit terminal 1 and the control circuit terminal 2.
  5. Verify the test lamp turns ON and OFF when cycling the ignition between ON and OFF.
    • If the test lamp is always OFF 
    1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
    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.
      • If less than 1 V
    3. Ignition OFF.
    4. 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 K20 Engine Control Module.
    • If the test lamp is always ON 
    1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K20 Engine 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.
      • If infinite resistance, replace the K20 Engine Control Module.
    • If the test lamp turns ON and OFF 
  6. Verify a test lamp does not illuminate between the ignition circuit terminal 5 and ground.
    • If the test lamp illuminates 

      Repair the short to voltage on the circuit.

    • If the test lamp does not illuminate 
  7. Ignition ON, connect a 40 A fused jumper wire between the B+ circuit terminal 3 and the ignition circuit terminal 5.
  8. Verify device is activated.
    • If the device is not activated 
    1. Ignition OFF, disconnect the harness connector at the device.
    2. Test for infinite resistance between the ignition circuit terminal 5 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the ignition circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the device.
    • If the device activates 
  9. Test or replace the KR75 Engine Controls Ignition Relay.

Diagnostic E

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the X51A Fuse Block - Instrument Panel.
  2. Ignition ON.
  3. Verify a test lamp illuminates between the B+ circuit terminal 55 and ground.
    • If the test lamp does not illuminate 
    1. 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.
    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, replace the T19 Power Supply Transformer.
    • If the test lamp illuminates 
  4. Connect the X51A Fuse Block - Instrument Panel.
  5. Enable battery saver mode (transport mode).
  6. Ignition OFF and all vehicle systems OFF, disconnect the in-line harness connector X200.
  7. Connect a test lamp between the control circuit terminal 38 and ground.
  8. Verify the test lamp momentarily flashes ON and OFF when turning the ignition ON.
    • If the test lamp is always OFF 
    1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K9 Body Control Module and KR104B Battery Saver Relay 2.
    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 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, remove the test lamp, disconnect the harness connector at the K9 Body Control Module, ignition ON.
    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.
      • If less than 1 V, replace the K9 Body Control Module.
    • If the test lamp turns ON and OFF 
  9. Connect a test lamp between the control circuit terminal 58 and ground.
  10. Verify the test lamp momentarily flashes ON and OFF after turning the ignition OFF.
    NOTE:

    It may take up to 1 min after the ignition is switched OFF and retained accessory power is disabled before the K9 Body Control Module sends a command to unlatch the relay.

    • If the test lamp is always OFF 
    1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K9 Body Control Module and KR104B Battery Saver Relay 2.
    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 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, remove the test lamp, disconnect the harness connector at the K9 Body Control Module, ignition ON.
    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.
      • If less than 1 V, replace the K9 Body Control Module.
    • If the test lamp turns ON and OFF 
  11. Connect the in-line harness connector X200.
  12. Disconnect the harness connector at the appropriate devices powered by the T19 Power Supply Transformer B+ supply circuit terminal 10 X1.
  13. Ignition ON.
  14. Verify that a test lamp illuminates between each of the B+ circuits listed below and ground.
      NOTE:

      The vehicle may not be equipped with all components as listed below. Use schematics to determine which components are supplied their B+ feed by the KR104A Battery Saver Relay 1. Use the connector end view to identify the B+ circuit terminal for each of those components.

    • K9 Body Control Module - B+ circuit terminal 1 X2
    • K41 Front and Rear Parking Assist Control Module - B+ circuit terminal 1 X1
    • S25 Garage Door Opener - B+ circuit terminal 1
    • A26 HVAC Controls - B+ circuit terminal 1
    • S136 Infotainment Control Touchpad - B+ circuit terminal 1
    • K48 Infotainment Faceplate Control Module - B+ circuit terminal 1 X1
    • K74 Human Machine Interface Control Module - B+ circuit terminal 7 X1
    • K73 Telematics Communication Interface Control Module - B+ circuit terminal 15 X1
    • P16 Instrument Cluster - B+ circuit terminal 7
    • X83 Auxiliary Audio Input - B+ circuit terminal 6 X1
    • P6 Clock - B+ circuit terminal 1
    • C2 Remote CD Changer - B+ circuit terminal 10
    • P29 Head-Up Display B+ circuit terminal 6 X1
    • A11 Radio - B+ circuit terminal 1 X1
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF, remove the test lamp.
    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, replace the X51A Fuse Block - Instrument Panel.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition OFF.
    2. Test for infinite resistance between the Ignition circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, test or replace the appropriate device powered by the T19 Power Supply Transformer B+ supply circuit terminal 10 X1.
    • If the test lamp illuminates 
  15. Test or replace the appropriate device powered by the T19 Power Supply Transformer B+ supply circuit terminal 10 X1.

Diagnostic F

  1. Ignition OFF and all vehicle systems OFF, disconnect the KR104B Battery Saver Relay 2. 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 6 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.
    • If less than 10 Ω 
  3. Ignition ON.
  4. Verify a test lamp illuminates between the B+ circuit terminal 3 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF, remove the test lamp.
    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 test lamp.
    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 KR104B Battery Saver Relay 2.
    • If the test lamp illuminates 
  5. Enable battery saver mode (transport mode).
  6. Ignition OFF.
  7. Connect a test lamp between the control circuit terminal 1 and ground.
  8. Verify the test lamp momentarily flashes ON and OFF when turning the ignition ON.
    • If the test lamp is always OFF 
    1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K9 Body Control Module and X51A Fuse Block - Instrument Panel.
    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 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, remove the test lamp, disconnect the harness connector at the K9 Body Control Module, ignition ON.
    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.
      • If less than 1 V, replace the K9 Body Control Module.
    • If the test lamp turns ON and OFF 
  9. Connect a test lamp between the control circuit terminal 2 and ground.
  10. Verify the test lamp momentarily flashes ON and OFF after turning the ignition OFF.
    NOTE:

    It may take up to 1 min after the ignition is switched OFF and retained accessory power is disabled before the K9 Body Control Module sends a command to unlatch the relay.

    • If the test lamp is always OFF 
    1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K9 Body Control Module and X51A Fuse Block - Instrument Panel.
    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 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, remove the test lamp, disconnect the harness connector at the K9 Body Control Module, ignition ON.
    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.
      • If less than 1 V, replace the K9 Body Control Module.
    • If the test lamp turns ON and OFF 
  11. Verify that a test lamp does not illuminate between the ignition circuit terminal 5 and ground.
    • If the test lamp illuminates 

      Repair the short to voltage on the ignition circuit

    • If the test lamp does not illuminate 
  12. Ignition ON, connect a 40 A fused jumper wire between the B+ circuit terminal 3 and the ignition circuit terminal 5.
  13. Verify device is activated.
    • If the device does not activate 
    1. Ignition OFF, disconnect the harness connector at the device.
    2. Test for infinite resistance between the ignition circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the ignition circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the device.
    • If the device activates 
  14. Test or replace the KR104B Battery Saver Relay 2.
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