The power window system consists of the following components:
• | Driver Door Switch (DDS) |
• | Passenger Door Switch (PDS) |
• | Body Control Module (BCM) |
• | Rear door power window switches |
• | Power window motors in each of the doors |
• | PWR WDO Circuit Breaker |
The power window system will operate anytime the Retained Accessory Power (RAP) system is active or when the ignition switch is in the ACCY or ON position.
The driver master control switches are integrated into the DDS. When a power window switch is activated in the up or down positions the DDS supplies power and ground to the window motor control circuits to drive the window motor in the required direction. Prior to activating a power window motor the DDS will supply the control circuit with a low current bias voltage in order to determine that a short to ground condition does not exist and during window motor operation the DDS continues to monitor the motor current to verify proper window motor operation.
The DDS controls the passenger window by a serial message to the PDS. When a power window switch is activated in the up or down positions the PDS supplies power and ground to the window motor control circuits to drive the window motor in the required direction. Prior to activating a power window motor the PDS will supply the control circuit with a low current bias voltage in order to determine that a short to ground condition does not exist, and during window motor operation the PDS continues to monitor the motor current to verify proper window motor operation. (Scan tool support is available for this system)
The switch for the driver power window has 3 positions Up, Down and Express Down and it's position is a direct input into the DDS. Upon receiving a request for power window operation (switch activation), the DDS supplies voltage to the power window motor up or down circuit and grounds the down or up circuit and the power window motor moves the window UP or DOWN direction.
The switch for the front passenger power window has 2 positions UP and DOWN, and it's position is a direct input into the PDS. Upon receiving a request for power window operation (switch activation), the PDS supplies voltage to the power window motor right front up or down circuit and grounds the opposite and the power window motor runs to drive the window UP or DOWN.
The front passenger power window can also be operated from the driver master control. The front passenger window switch on the driver master control has 2 positions UP and DOWN and it's position is a direct input into the DDS. Upon receiving a request for front passenger power window operation, the DDS transmits a serial message indicating the changed switch position. When the PDS receives this message, the PDS supplies voltage to the power window motor right front up or down circuit and grounds the opposite and the power window motor runs to move the window UP or DOWN.
The body control module (BCM) monitors the window UP/DOWN command from the DDS. When the rear window UP or DOWN command is received, the BCM sends a signal to the appropriate rear window switch. The rear window switches continuously monitor the up and down signal circuits, if no function is being commanded, the signal voltage is at approximately B+ voltage. If the UP or DOWN function is commanded, the BCM signal voltage drops approximately 5 volts and the appropriate rear window switch will then command the window in the UP or DOWN direction.
The BCM monitors the window lockout command from the DDS. When the rear window switch operation is authorized, the BCM sends a signal to the rear window switches allowing for normal window operation from the rear switches. If the rear window lockout function is commanded, the BCM signal voltage drops approximately 5 volts which disables the rear window switches and the rear windows will only operate when the BCM receives a command from the driver master control. The lockout feature will remain in effect until the ignition switch is cycled or the driver enables the rear windows by pressing the rear window lockout switch again.