Power Window System Components
The power window system consists of the following components:
| • | Driver door module (DDM) |
| • | Passenger door module (PDM) |
| • | Body control module (BCM) |
| • | Rear door power window switches (crew cab) |
| • | Power window motors in each of the doors (circuit breaker protected) |
| • | LT DRS Circuit Breaker |
| • | RT DOORS Circuit Breaker |
Power Window System Controls
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 driver door module (DDM). When a power window switch is activated in the up or down positions the DDM 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 DDM 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 DDM continues to monitor the motor current to verify proper window motor operation.
The DDM controls the passenger window through a serial data message to the passenger door module (PDM). When a power window switch is activated in the up or down positions the PDM 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 PDM 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 PDM continues to monitor the motor current to verify proper window motor operation. Scan tool support is available for this system.
Power Window Motor Operation
A permanent magnet motor operates each of the power side windows. Each motor raises or lowers the glass when the motor receives voltage. The direction the motor turns depends on the polarity of the supply voltage. The power window switches control the polarity of the supply voltage. A built-in circuit breaker protects each motor. The circuit breaker opens when the switch is depressed for a extended period of time under the following conditions:
| • | The window has an obstruction. |
| • | The window is fully open or fully closed. |
The circuit breaker will reset automatically as the circuit breaker cools.
Driver Power Window Operation
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 driver door module (DDM). Upon receiving a request for power window operation (switch activation), the DDM 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.
Front Passenger Power Window Operation
The switch for the front passenger power window has 2 positions, UP and DOWN, and it's position is a direct input into the passenger door module (PDM). Upon receiving a request for power window operation (switch activation), the PDM 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 driver door module (DDM). Upon receiving a request for front passenger power window operation, the DDM transmits a serial data message indicating the changed switch position. When the PDM receives this message, the PDM 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.
Rear Passenger Power Window Operation (Crew Cab)
The body control module (BCM) monitors the window UP/DOWN command from the DDM. 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.
Rear Power Window Lockout Operation (Crew Cab)
The body control module (BCM) monitors the window lockout command from the driver door module (DDM). 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.
