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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 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. 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 S79D Window Switch-Driver 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 
  6. Install a 3 A fused jumper wire between the signal circuit terminal 3 and the ground circuit terminal 1.
  7. Verify the scan tool Driver Window Main Control Down Switch parameter is Active
    • If not Active 
    1. Ignition OFF, remove the 3 A fused jumper wire, disconnect the harness connector at the M74D Window Motor-Driver, ignition ON.
    2. Test for less than 1 V between the S79D Window Switch-Driver signal circuit terminal 3 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 
  8. 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 S79D Window Switch-Driver 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 
  9. Install a 3 A fused jumper wire between the signal circuit terminal 6 and the ground circuit terminal 1.
  10. Verify the scan tool Driver Window Main Control Up Switch parameter is Active
    • If not Active 
    1. Ignition OFF, remove the 3 A fused jumper wire, disconnect the harness connector at the M74D Window Motor-Driver, ignition ON.
    2. Test for less than 1 V between the S79D Window Switch-Driver signal circuit 6 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 
  11. 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 S79D Window Switch-Driver 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 
  12. Install a 3 A fused jumper wire between the signal circuit terminal 2 and the ground circuit terminal 1.
  13. Verify the scan tool Driver Window Main Control Express Switch parameter is Active
    • If not Active 
    1. Ignition OFF, remove the 3 A fused jumper wire, disconnect the harness connector at the M74D Window Motor-Driver, ignition ON.
    2. Test for less than 1 V between the S79D Window Switch-Driver signal circuit 2 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 
  14. 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 not Inactive 
    1. Ignition OFF, disconnect the harness connector at the M74P Window Motor-Passenger
    2. Test for infinite resistance between the signal circuit terminal listed below and ground:
      • S79P Window Switch-Passenger - signal circuit terminal 7
      • S79P Window Switch-Passenger - signal circuit terminal 8
      • 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 8 and ground:
  6. Verify the scan tool Passenger Window Switch at Door parameter is Up
    • If not Up 
    1. Ignition OFF, remove the fused jumper wire, disconnect the harness connector at the M74P Window Motor-Passenger, ignition ON.
    2. Test for less than 1 V between the S79P Window Switch-Passenger 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. Ignition OFF, 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 Up 
  7. Install a 3 A fused jumper wire between the signal circuit terminal 7 and ground.
  8. Verify the scan tool Passenger Window Switch at Door parameter is Down
    • If not Down 
    1. Ignition OFF, remove the fused jumper wire, disconnect the harness connector at the M74P Window Motor-Passenger, ignition ON.
    2. Test for less than 1 V between the S79P Window Switch-Passenger 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. Ignition OFF, 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
    • 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 S79P Window Switch-Passenger signal circuit 6 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.

Rear Power Window Inoperative

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate S79 Window Switch-Rear. 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 5 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 8.
    • 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 S79 Window Switch-Rear
    • If the test lamp illuminates 
  5. Ignition OFF, connect the harness connector at the S79 Window Switch-Rear and disconnect the harness connector at the M74 Window Motor-Rear.
  6. Test for less than 5 Ω between the control circuit terminal 1 and ground.
    • If 5 Ω or greater 
    1. Ignition OFF, disconnect the harness connector at the S79 Window Switch-Rear.
    2. 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 S79 Window Switch-Rear.
    • If less than 5 Ω 
  7. Test for less than 5 Ω between the control circuit terminal 2 and ground.
    • If 5 Ω or greater 
    1. Ignition OFF, disconnect the harness connector at the S79 Window Switch-Rear.
    2. 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 S79 Window Switch-Rear.
    • If less than 5 Ω 
  8. Connect a test lamp between the control circuit terminal 1 and control circuit terminal 2, ignition ON.
  9. Verify the test lamp turns ON when commanding the UP and DOWN states with the S79 Window Switch-Rear.
    • If the test lamp remains OFF during either of the commands 
    1. Ignition OFF, remove the test lamp, disconnect the harness connector at the S79 Window Switch-Rear.
    2. Test for infinite resistance between each control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the S79 Window Switch-Rear.
    • If the test lamp is always ON 
  10. Ignition OFF, remove the test lamp, disconnect the harness connector at the S79 Window Switch-Rear, ignition ON.
  11. Test for less than 1 V between each control circuit and ground.
    • If 1 V or greater, repair the short to voltage on the circuit.
    • If less than 1 V, replace the S79 Window Switch-Rear
    • If the test lamp turns ON during each of the commands 
  12. Test or replace the M74 Window Motor-Rear.
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