Circuit/System Testing
Driver Window Motor Malfunction
- Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the M74D Window Motor-Driver. It may take up to 2 minutes for all vehicle systems to power down.
- Test for less than 10 Ω between the ground circuit terminal 1 and ground.
- If 10 Ω or greater
- Ignition OFF.
- 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
- Ignition ON.
- 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
- Ignition OFF.
- 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
- Ignition OFF.
- Test for infinite resistance between the B+ circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If the test lamp illuminates
- Test or replace the M74D Window Motor-Driver.
Driver Window Switch Malfunction
- 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.
- Test for less than 10 Ω between the ground circuit terminal 1 and ground.
- If 10 Ω or greater
- Ignition OFF.
- 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
- Ignition ON.
- 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
- Ignition OFF.
- 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
- Ignition OFF.
- 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, test or replace the S79D Window Switch-Driver.
- If the test lamp illuminates
- Verify the scan tool Driver Window Main Control Down Switch parameter is Inactive.
- If not Inactive
- Ignition OFF, disconnect the harness connector at the M74D Window Motor-Driver.
- 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
- Install a 3 A fused jumper wire between the signal circuit terminal 3 and the ground circuit terminal 1.
- Verify the scan tool Driver Window Main Control Down Switch parameter is Active
- If not Active
- Ignition OFF, remove the 3 A fused jumper wire, disconnect the harness connector at the M74D Window Motor-Driver, ignition ON.
- 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
- 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
- Verify the scan tool Driver Window Main Control Up Switch parameter is Inactive.
- If not Inactive
- Ignition OFF, disconnect the harness connector at the M74D Window Motor-Driver.
- 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
- Install a 3 A fused jumper wire between the signal circuit terminal 6 and the ground circuit terminal 1.
- Verify the scan tool Driver Window Main Control Up Switch parameter is Active
- If not Active
- Ignition OFF, remove the 3 A fused jumper wire, disconnect the harness connector at the M74D Window Motor-Driver, ignition ON.
- Test for less than 1 V between the S79D Window Switch-Driver signal circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V
- 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
- Verify the scan tool Driver Window Main Control Express Switch parameter is Inactive.
- If not Inactive
- Ignition OFF, disconnect the harness connector at the M74D Window Motor-Driver.
- 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
- Install a 3 A fused jumper wire between the signal circuit terminal 2 and the ground circuit terminal 1.
- Verify the scan tool Driver Window Main Control Express Switch parameter is Active
- If not Active
- Ignition OFF, remove the 3 A fused jumper wire, disconnect the harness connector at the M74D Window Motor-Driver, ignition ON.
- Test for less than 1 V between the S79D Window Switch-Driver signal circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V
- 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
- Test or replace the S79D Window Switch-Driver.
Passenger Power Window Inoperative
- Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate passenger or rear S79 Window Switch. It may take up to 2 minutes for all vehicle systems to power down.
- Test for less than 10 Ω between the ground circuit terminal listed below and ground:
- S79P Window Switch-Passenger - ground circuit terminal 1
- S79LR Window Switch-Left Rear - ground circuit terminal 5
- S79RR Window Switch-Right Rear - ground circuit terminal 5
- If 10 Ω or greater
- Ignition OFF.
- 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
- Ignition ON.
- Verify a test lamp illuminates between the B+ circuit terminal listed below and ground:
- S79P Window Switch-Passenger - B+ circuit terminal 4
- S79LR Window Switch-Left Rear - B+ circuit terminal 8
- S79RR Window Switch-Right Rear - B+ circuit terminal 8
- If the test lamp does not illuminate and the circuit fuse is good
- Ignition OFF.
- 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
- Ignition OFF.
- 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.
- If the test lamp illuminates
- Ignition OFF, connect the harness connector at the S79 Window Switch and disconnect the harness connector at the M74 Window Motor.
- Test for less than 5 Ω between the control circuit terminal A and ground.
- If 5 Ω or greater
- Ignition OFF, disconnect the harness connector at the S79 Window Switch.
- 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.
- If less than 5 Ω
- Test for less than 5 Ω between the control circuit terminal B and ground.
- If 5 Ω or greater
- Ignition OFF, disconnect the harness connector at the S79 Window Switch.
- 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.
- If less than 5 Ω
- Connect a test lamp between control circuit terminal A and control circuit terminal B, ignition ON.
- Verify the test lamp turns ON when commanding the UP and DOWN states with the S79 Window Switch.
- If the test lamp remains OFF during either of the commands
- Ignition OFF, remove the test lamp, disconnect the harness connector at the S79 Window Switch.
- 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.
- If the test lamp turns ON during each of the commands
- Test or replace the M74 Window Motor.