Power Windows Malfunction (AEC)
Power Windows Malfunction (AEC)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
When the ignition switch is in the RUN or ACCY position, or retained accessory power is enabled and the driver or passenger window switch or rear window switch is pressed in the down position, voltage is applied to the appropriate window motor causing that window to open. When the driver or passenger window switch is pulled in the up position, voltage is applied to the appropriate window motor in the opposite direction causing that window to close.
When the driver wishes to command a passenger or rear window, a window switch is pressed on the driver window switch. A serial data message is then sent to the body control module (BCM) from the driver window switch. The BCM will examine the request and check for messages from other power window switches that may prohibit the window movement. If no prohibitive messages have been received, the BCM will send a serial data message to the passenger or rear window switch which will command the window motor to perform as requested.
Reference Information
Schematic Reference
Moveable Window Schematics Electrical Diagrams
Connector End View Reference
Component Connector End Views Sunshade - Left (D61)
Description and Operation
Power Windows Description and Operation Power Windows
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify the driver, passenger, left rear and right rear window move while commanding the window UP and DOWN with a scan tool.
• If the window does not move UP and DOWN as commanded
Refer to Circuit/System Testing.
• If the window moves UP and DOWN as commanded
3. Verify the scan tool Left Rear Main Control Down Switch, Left Rear Main Control Express Switch, Left Rear Main Control Up Switch, Right Rear Main Control Down Switch, Right Rear Main Control Express Switch, Right Rear Main Control Up Switch, Front Passenger Main Control Down Switch, Front Passenger Main Control Express Switch, and the Front Passenger Main Control Up Switch parameter changes between Inactive and Active when pressing and pulling each switch on the driver window switch.
• If the parameters do not change
Replace the S79D window switch-driver.
• If the parameters change
4. Verify the scan tool Child Security Lockout Switch parameter changes between Inactive and Active when pressing the window lockout switch.
• If the parameter does not change
Refer to Power Door Child Lock Malfunction Power Door Child Lock Malfunction.
• If the parameter changes
5. Verify the lockout indicator turns ON and OFF when commanding the Child Security Lock Indicator ON and OFF with a scan tool.
• If the indicator does not turn ON and OFF
Replace the S79D window switch-driver.
• If the indicator turns ON and OFF
6. Command the rear window lockout by pressing the window lockout switch on the driver window switch.
7. Verify the left rear and right rear window does not move while commanding the window UP and DOWN with the left rear window switch and right rear window switch.
• If a rear window moves UP and DOWN as commanded
Refer to Power Door Child Lock Malfunction Power Door Child Lock Malfunction.
• If the rear windows do not move UP and DOWN
8. All OK.
Circuit/System Testing
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate S79 window switch. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohms between the ground circuit terminal listed below and ground:
* S79D window switch-driver - ground circuit terminal 1
* 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 ohms or greater
1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 10 ohms
3. Ignition ON.
4. Verify a test lamp illuminates between the B+ circuit terminal listed below and ground:
* S79D window switch-driver - B+ circuit terminal 4
* 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
1. Ignition OFF.
2. Test for less than 2 ohms in the B+ circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, 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
3. 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, replace the S79 window switch
• If the test lamp illuminates
5. Test for 5-10 V between the serial data circuit terminal listed below and ground
* S79D window switch-driver - serial data circuit terminal 5
* S79P window switch-passenger - serial data circuit terminal 5
* S79LR window switch-left rear - serial data circuit terminal 1
* S79RR window switch-right rear - serial data circuit terminal 1
• 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 and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohms in the serial data circuit end to end.
• If 2 ohms or greater, repair the open/high resistance on the circuit.
• If less than 2 ohms, 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. Ignition OFF connect the harness connector at the S79 window switch and disconnect the harness connector at the M74 window motor.
7. Test for less than 5 ohms between the control circuit terminal 1 and ground.
• If 5 ohms or greater
1. Ignition OFF, disconnect the harness connector at the S79 window switch.
2. Test for less than 2 ohms in the control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the S79 window switch.
• If less than 5 ohms
8. Test for less than 5 ohms between the control circuit terminal 2 and ground.
• If 5 ohms or greater
1. Ignition OFF, disconnect the harness connector at the S79 window switch.
2. Test for less than 2 ohms in the control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the S79 window switch.
• If less than 5 ohms
9. Connect a test lamp between the control circuit terminal 1 and control circuit terminal 2, ignition ON.
10. Verify the test lamp illuminates when commanding the UP and DOWN states with the S79 window switch.
• If the test lamp does not illuminate during either of the commands
1. Ignition OFF, disconnect the harness connector at the S79 window switch.
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.
• If the test lamp illuminates during each of the commands
11. Test or replace the M74 window motor.
Component Testing
Window Motor
1. Ignition OFF, disconnect the harness connector at the appropriate M74 window motor.
2. Install a 25 A fused jumper wire between one of the control terminals and 12 V. Momentarily install a jumper wire between the other control terminal and ground. Reverse the jumper wires at least two times, the M74 window motor should perform the UP and DOWN functions.
• If the function does not perform the UP and DOWN functions
Replace the M74 window motor.
• If the function performs the UP and DOWN functions
3. All OK
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Front Side Door Window Regulator Motor Replacement Service and Repair
* Rear Side Door Window Regulator Motor Replacement Service and Repair
* Rear Side Door Window Switch Replacement Rear Side Door Window Switch Replacement
* Front Side Door Window Switch Replacement - Right Side Front Side Door Window Switch Replacement - Right Side
* Front Side Door Window Switch Replacement - Left Side Front Side Door Window Switch Replacement - Left Side