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 (RAP) 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.
Reference Information
Schematic Reference
Moveable Window Schematics Electrical Diagrams
Connector End View Reference
Component Connector End Views Sunshade - Left (DH6)
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, observe the scan tool parameters listed below while using left front, right front, left rear and right rear switches on the window switch-driver. The parameters for each switch should change from Inactive to Active.
* Driver Window Main Control Up Switch parameter
* Driver Window Main Control Express Switch parameter
* Driver Window Main Control Down Switch parameter
* Front Passenger Main Control Down Switch parameter
* Front Passenger Main Control Express Switch parameter
* Front Passenger Main Control Up Switch parameter
* Left Rear Main Control Down Switch parameter
* Left Rear Main Control Express Switch parameter
* Left Rear Main Control Up Switch parameter
* Right Rear Main Control Down Switch parameter
* Right Rear Main Control Express Switch parameter
* Right Rear Main Control Up Switch parameter
• If the parameters do not change or if the parameter is No Communication, refer to Window Switch Malfunction.
2. Observe the appropriate scan tool Window Switch at Door parameter while using the window switch-passenger, window switch-left rear and window switch-right rear. The parameters for each window switch should change from Inactive to Up, Down and Express.
• If the parameters do not change or if the parameter is No Communication, refer to Window Switch Malfunction.
3. Command each window UP and DOWN by using their respective window switch, each window should perform the UP and DOWN functions from each switch.
• If a window does not perform as specified, refer to Window Motor Malfunction.
Circuit/System Testing
Window Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the appropriate S79 window switch.
2. Test for less than 15 ohms between the ground circuit terminal listed below and ground:
* S79D window switch-driver terminal 1
* S79P window switch-passenger terminal 1
* S79LR window switch-left rear terminal 5
* S79RR window switch-right rear terminal 5
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal listed below and ground:
* S79D window switch-driver terminal 4
* S79P window switch-passenger terminal 4
* S79LR window switch-left rear terminal 8
* S79RR window switch-right rear terminal 8
• If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
4. Test for 6.5-9 V between the LIN circuit terminal listed below and ground.
* S79D window switch-driver terminal 5
* S79P window switch-passenger terminal 5
* S79LR window switch-left rear terminal 1
* S79RR window switch-right rear terminal 1
• If greater than the specified range, test the LIN circuit for a short to voltage. If the circuit tests normal, replace the K9 body control module.
• If less than the specified range, test the LIN circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 body control module.
5. If all circuits test normal, test or replace the S79 window switch.
Window Motor Malfunction
1. Ignition OFF, disconnect the harness connector at the appropriate M74 window motor.
2. Test for less than 15 ohms between the control circuit terminal A and ground.
• If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the appropriate S79 window switch.
3. Test for less than 15 ohms between the control circuit terminal B and ground.
• If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the appropriate S79 window switch.
4. Connect a test lamp between the control circuit terminal A and control circuit terminal B.
5. Ignition ON, command the M74 window motor UP and DOWN by using the S79 window switch. The test lamp should briefly illuminate during the UP and DOWN commands.
• If the test lamp does not illuminate during the UP or DOWN command, test either control circuit for a short to ground. If the circuits tests normal, replace the S79 window switch.
6. If all circuits test normal, 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 it does not perform as specified, replace the M74 window motor.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* 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 (Passengers Side Door) Front Side Door Window Switch Replacement (Passengers Side Door)
* Front Side Door Window and Multifunction Switch Replacement (Drivers Side Door) Front Side Door Window and Multifunction Switch Replacement (Drivers Side Door)
* Control Module References Control Module References for the BCM replacement, programming and setup