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Circuit/System Testing

Driver/Passenger Window Motor Malfunction

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate driver or passenger M74 window motor. It may take up to 2 minutes 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 2 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF.
    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.
    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 M74 window motor.
    • If the test lamp illuminates 
  5. Test for 5-10 V between the serial data circuit terminal 4 and ground
    • If less than 5 V 
    1. Ignition OFF, disconnect the harness connector at the K9 body control module.
    2. Test for infinite resistance between the serial data 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 serial data circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance on the circuit.
      • If less than 2 Ω, replace the K9 body control module.
    • If greater than 10 V 
    1. Ignition OFF, disconnect the harness connector at the K9 body control module, ignition ON.
    2. Test for less than 1 V between the serial data 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 between 5-10 V 
  6. Test or replace the M74 window motor.

Driver Window Switch Malfunction

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the S79D window switch-driver. It may take up to 2 minutes 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 4 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF.
    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.
    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 S79D window switch-driver
    • If the test lamp illuminates 
  5. Test for 5-10 V between the serial data circuit terminal 5 and ground
    • If less than 5 V 
    1. Ignition OFF, disconnect the harness connector at the K9 body control module.
    2. Test for infinite resistance between the serial data 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 serial data circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance on the circuit.
      • If less than 2 Ω, replace the K9 body control module.
    • If greater than 10 V 
    1. Ignition OFF, disconnect the harness connector at the K9 body control module, ignition ON.
    2. Test for less than 1 V between the serial data signal 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 between 5-10 V 
  6. Verify the scan tool Driver Window Main Control Down Switch parameter is Inactive.
    • If not Inactive 
    1. Ignition OFF, disconnect the harness connector at the M74D window motor-driver.
    2. Test for infinite resistance between the signal circuit terminal 3 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the M74D window motor-driver.
    • If Inactive 
  7. Install a 3 A fused jumper wire between the signal circuit terminal 3 and the ground circuit terminal 1.
  8. Verify the scan tool Driver Window Main Control Down Switch parameter is Active
    • If not Active 
    1. Ignition OFF, disconnect the harness connector at the M74D window motor-driver, ignition ON.
    2. Test for less than 1 V between the signal circuit terminal 7 and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • 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 M74D window motor-driver.
    • If Active 
  9. Verify the scan tool Driver Window Main Control Up Switch parameter is Inactive.
    • If not Inactive 
    1. Ignition OFF, disconnect the harness connector at the M74D window motor-driver.
    2. Test for infinite resistance between the signal circuit terminal 6 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the M74D window motor-driver.
    • If Inactive 
  10. Install a 3 A fused jumper wire between the signal circuit terminal 6 and the ground circuit terminal 1.
  11. Verify the scan tool Driver Window Main Control Up Switch parameter is Active
    • If not Active 
    1. Ignition OFF, disconnect the harness connector at the M74D window motor-driver, ignition ON.
    2. Test for less than 1 V between the signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • 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 M74D window motor-driver.
    • If Active 
  12. Verify the scan tool Driver Window Main Control Express Switch parameter is Inactive.
    • If not Inactive 
    1. Ignition OFF, disconnect the harness connector at the M74D window motor-driver.
    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 M74D window motor-driver.
    • If Inactive 
  13. Install a 3 A fused jumper wire between the signal circuit terminal 2 and the ground circuit terminal 1.
  14. Verify the scan tool Driver Window Main Control Express Switch parameter is Active
    • If not Active 
    1. Ignition OFF, disconnect the harness connector at the M74D window motor-driver, ignition ON.
    2. Test for less than 1 V between the signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • 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 M74D window motor-driver.
    • If Active 
  15. Test or replace the S79D window switch-driver.

Passenger Window Switch Malfunction

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the S79P window switch-passenger. It may take up to 2 minutes 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 the scan tool Passenger Window Switch at Door parameter is Inactive.
    • If the value is UP 
    1. Ignition OFF, disconnect the harness connector at the M74P window motor-passenger.
    2. Test for infinite resistance between the signal circuit terminal 8 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the M74P window motor-passenger.
    • If the value is Down 
    1. Ignition OFF, disconnect the harness connector at the M74P window motor-passenger.
    2. Test for infinite resistance between the signal circuit terminal 7 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the M74P window motor-passenger.
    • If Inactive 
  5. Install a 3 A fused jumper wire between the signal circuit terminal 7 and the ground circuit terminal 1.
  6. Verify the scan tool Passenger Window Switch at Door parameter is Down
    • If Inactive 
    1. Ignition OFF, disconnect the harness connector at the M74P window motor-passenger, ignition ON.
    2. Test for less than 1 V between the signal circuit terminal 7 and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • 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 M74P window motor-passenger.
    • If Down 
  7. Install a 3 A fused jumper wire between the signal circuit terminal 8 and ground circuit terminal 1.
  8. Verify the scan tool Passenger Window Switch at Door parameter is Up
    • If Inactive 
    1. Ignition OFF, disconnect the harness connector at the M74P window motor-passenger, ignition ON.
    2. Test for less than 1 V between the signal circuit terminal 8 and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • 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 M74P window motor-passenger.
    • If Down 
  9. Test for greater than 10 V between the signal circuit terminal 6 and ground circuit terminal 1.
    • If less than 10 V 
    1. Ignition OFF, disconnect the harness connector at the M74P window motor-passenger.
    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 2 Ω in the signal circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance on the circuit.
      • If less than 2 Ω, replace the M74P window motor-passenger.
    • If greater than 10 V 
  10. Test or replace the S79P window switch-passenger.
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