Part 1
Power Windows Malfunction
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
The driver side window consists of a driver window switch and a window motor capable of express up and express down functions. When the driver window switch is pressed or pulled, the voltage within the appropriate signal circuit drops and the window motor will then perform the commanded function.
The driver power window switch contains individual window switches for each of power windows. All windows may be controlled up and down from the driver power window switch. The individual passenger power window switches will only control the up and down operation of their respective power window.
Each power window contains a reversible power window motor. The direction the window travels is dependent upon the polarity of the supply voltage. By reversing polarity of the supply voltage the window motor will move up or down. Each power window motor is internally circuit breaker protected.
Battery voltage is supplied to the power window switch through the accessory voltage supply circuit. The power window switch also receives a constant ground source. The power window motor control circuits are connected to ground through the normally closed up and down contacts of the power window switch. When the power switch is placed in the down position, the power window motor down control circuit is switched to 12 V and is applied to the down side of the power window motor. Since the other side of the power motor is connected to ground through the normally closed contacts of the up switch, the window travels down. By placing the power window switch in the up position, the polarity of the power window motor is reversed and the window travels up.
Diagnostic Aids
A window motor that has not been normalized will no longer perform the express up and express down functions, this may occur during the following conditions:
* When a window motor has been disconnected
* When a door harness has been disconnected
* When the battery has been disconnected or replaced
To normalize the window motor refer to Window Motor Programming - Express Function Testing and Inspection.
Reference Information
Schematic Reference
Moveable Window Schematics Electrical Diagrams
Connector End View Reference
Component Connector End Views Fuel Pump and Level Sensor Assembly
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 M74D Window Motor-Driver functions while commanding the Driver Window Motor Up and Down with a scan tool.
• If the M74D Window Motor-Driver does not move UP and DOWN as commanded
Refer to Circuit/System Testing - Driver Window Motor Malfunction.
• If the M74D Window Motor-Driver moves UP and DOWN as commanded
3. Verify the M74D Window Motor-Driver moves while commanding the window UP and DOWN with the S79D Window Switch-Driver.
• If the M74D Window Motor-Driver does not move UP and DOWN as commanded
Refer to Circuit/System Testing - Driver Window Switch Malfunction.
• If the M74D Window Motor-Driver moves UP and DOWN as commanded
4. Verify the M74D Window Motor-Driver performs the express UP and express DOWN functions with the S79D Window Switch-Driver.
• If the driver window does not express UP or express DOWN
Normalize the M74D Window Motor-Driver, refer to Window Motor Programming - Express Function Testing and Inspection.
1. Verify the M74D Window Motor-Driver performs the express UP and express DOWN functions with the S79D Window Switch-Driver
• If the M74D Window Motor-Driver does not express UP or express DOWN
Refer to Circuit/System Testing - Driver Window Switch Malfunction.
• If the M74D Window Motor-Driver performs the express UP and express DOWN functions
5. Verify the M74P Window Motor-Passenger performs the UP and DOWN functions at both the S79D Window Switch-Driver and S79P Window Switch-Passenger.
• If the M74P Window Motor-Passenger is inoperative from both the S79D Window Switch-Driver and S79P Window Switch-Passenger
Refer to Circuit/System Testing - Passenger Window Inoperative From Both Switches.
• If the M74P Window Motor-Passenger is inoperative from the S79P Window Switch-Passenger only
Refer to Circuit/System Testing - Passenger Window Inoperative From A Single Switch.
• If the M74P Window Motor-Passenger is inoperative from the S79D Window Switch-Driver only
Refer to Circuit/System Testing - Passenger Window Inoperative From A Single Switch.
• If the M74P Window Motor-Passenger performs the UP and DOWN functions at both S79D Window Switch-Driver and S79P Window Switch-Passenger
6. Verify the left rear and right rear M74 Window Motor performs the UP and DOWN functions at both the S79D Window Switch-Driver and each of the rear S79 Window Switch.
• If a M74 Window Motor is inoperative from both the driver and rear window switch
Refer to Circuit/System Testing - Rear Window Inoperative From Both Switches
• If a rear M74 Window Motor is inoperative from the rear window switch only
Refer to Circuit/System Testing - Rear Window Switch Inoperative
• If a M74 Window Motor is inoperative from the driver window switch only
Test or replace the S79D Window Switch-Driver.
• If the M74 Window Motor performs the UP and DOWN functions at both the S79D Window Switch-Driver and the rear S79 Window Switch
7. Lock out the rear window switches by pressing the lockout switch on the S79D Window Switch-Driver.
8. Verify the left rear and right rear M74 Window Motor is inoperative at both of the rear S79 Window Switch.
• If both rear M74 Window Motor continue to function from the rear S79 Window Switch
Refer to Circuit/System Testing - Rear Window Lockout Inoperative
• If both rear M74 Window Motor is inoperative from the rear S79 Window Switch
9. All OK.