The vehicle is equipped with power windows controlled by the door modules. If the driver door module (DDM) receives a window switch request from one of the window switches built into the driver door switch assembly (DDSA), the DDM checks the Class 2 serial data to see if the status information is correct (i.e. ignition switch position) to permit window operation to occur. If the status information is correct, the DDM, either supplies power and ground to its associated window motor, or sends a command via the power door serial data line to the passenger door module controlling the window. The passenger door module controlling the window then supplies power and ground to its associated window motor to move the window as requested.

When one of the local window switches mounted on one of the passenger doors is operated, the associated door module examines the request and checks to see if there are any messages from the DDM prohibiting the movement. If conditions are correct, and no prohibitive messages have been received from the DDM, the associated door module then supplies power and ground to its associated window motor to move the window as requested.

In order to control power window operations, as well as other door functions, door modules must be powered up. Battery voltage is supplied from the rear fuse block, through separate circuits, to each door module. Each door module is separately grounded through a ground stake. The door modules also use these voltage and ground supplies to provide power and ground to their associated window and lock switches. The front door modules, in addition, use these voltage and ground supplies for outside rearview mirror operations.

The DDM battery voltage circuit is fed by the DRVMDL 10 amp fuse in the Rear Fuse Block.

The PDM battery voltage circuit is fed by the PASS MDL 10 amp fuse in the Rear Fuse Block.

The LRDM battery voltage circuit and the RRDM battery voltage circuit are both fed by the RRDR MDL 10 amp fuse in the Rear Fuse Block.

These circuits are in the C1 harness connector of each door module and must not be confused with the door modules voltage and ground circuits that are used exclusively to drive the power window motors. For more information concerning power window motor power and grounds, see the appropriately titled paragraph following.

Each passenger door has a power window switch mounted to it. In order to receive a signal from the associated switch, the passenger door modules, PDM, LRDM, and RRDM each supply battery voltage and ground to their associated power window switch. There are three circuits for voltage between each passenger door power window switch and its associated door module, one for an Up signal, one for a Down signal, and one for an Express signal. The door modules each supply ground to their switch via a fourth circuit. When the switch is activated for an Up, Down, or Express function, the normally open switch contacts for that function are closed, and voltage flows through the switch, providing the associated door module with the neccessary signal.

The driver door switch assembly (DDSA) contains the only power window switch for the driver door window, however, the DDSA contains a window switch for each of the vehicles passenger doors as well. These switches differ from the individual power window switches mounted locally to the passenger doors in that, there are no external circuits. The DDSA window switches get their power and ground from the DDM. When a power window switch on the DDSA is operated, the normally open switch contacts for that function are closed to ground, and battery voltage flows through the switch. The DDSA interprets the switch signal and sends the appropriate window request to the DDM via the power door serial data circuit. The DDM then sends the request message, via the power door serial data circuit, to the appropriate door module to operate the associated window.

Each door module has its own separate battery positive voltage supply circuit, used exclusively for power window motor operation. Although theses circuits are separate, they are all fed by the same PWR WDO 30 amp circuit breaker located in the rear fuse block. Each door module also has a separate ground circuit used exclusively for power window motor operation. When a door module drives a power window motor, the door module internally connects these voltage and ground circuits to the appropriate window motor control circuits. The battery voltage and ground circuits designated for window motor operation are in the C5 harness connector of each door module, and must not be confused with the battery voltage and ground circuits of the C1 harness connector.

Each door module applies battery voltage and ground, through the window motor control circuits, to its associated window motor. The window motors are reversible. The direction the window moves depends on which motor control circuit the voltage is applied to, and which motor control circuit the ground is applied to. To move the window in the Up direction, the module applies voltage to the window motor Up control circuit, and ground to the window motor Down control circuit. When a window movement in the opposite direction is needed, the module reverses the polarity and applies voltage and ground to the opposite circuits to move the window in the reverse direction. During a window Express operation, the door module applies the voltage and ground to the window motor until the window is either fully open or fully closed.

All of the windows have the Express Down feature. This allows the windows to be fully opened by momentarily pressing the window switch to the second detente of the Down position. Both the Down contacts and the Express contacts of the switch are closed. If a passenger door window is operated from its locally mounted window switch, the door module associated with the switch interprets this two contact signal as an Express Down request. If a window is operated from the driver door, the DDSA interprets the two contact switch signal and sends it on, via the class 2 serial data circuit, to the appropriate door module.

The driver door module (DDM) and the passenger front door module (PDM) have the Express Up feature. This allows the front door windows to be fully closed without holding the switch to the Up position for the entire window Up cycle. Each of the front door window motors has a window sensor mounted to it. The window sensors detect differences in their respective window motors electrical pulses to determine if there is an obstruction to the travel of its window glass. If one of the sensors detects that a passenger, or other obstacle, has become trapped between the window and window frame, it sends this information, via two communication circuits, to its associated door module. The door module then takes the appropriate action and, either disables the Express Up function, or reverses the direction of window travel.

Each front door module and the corresponding sensor are wired to each other by four separate circuits in order to control the Express Up function. Each front door module supplies battery voltage, via the window sensor battery positive voltage circuit, and ground, via the window sensor low reference circuit, to the sensor. Each door module communicates with its sensor via the other two separate and unique communication circuits. The communication circuits are, the power window high speed serial data circuit, which is a one-way communications line from the sensor to the module, and, the power window low speed serial data circuit, which is a two-way communications line that carries information both ways, from the sensor to the module, and, from the module to the sensor. These communication lines are used to communicate the direction the window is moving in, state-of-health messages, and, to communicate the actual position of the window glass in relationship to the distance traveled by the window.

If a front door module looses power for any reason, such as a vehicle battery disconnect, the window sensor/motor assembly must be reprogrammed once power has been restored to the door module. Refer to Window Motor Programming - Express Function .

The rear window lockout switch is built into the Driver Door Switch Assembly (DDSA). There are no external circuits. The lockout function is used to prevent the rear passenger door windows from being operated from their locally mounted switches. When the lockout switch is pressed momentarily, the switch contacts are breifly closed, the LED indicator on the switch button is illuminated, and the DDSA interprets the flow of voltage through the switch as a lockout request. The DDSA sends the switch status, via the power door serial data circuit, to the driver door module (DDM). The DDM sends the request, via the power door serial data circuit to the rear passenger door modules. The rear door modules then prohibit the windows from being operated from their locally mounted window switches. .

When the lockout function has been activated, the rear passenger door windows can still be operated from the driver door by using the window switches built into the DDSA