Power Windows System Components
The following components are used to control the power windows:
• | Driver door module (DDM) |
• | Passenger front door module (PDM) |
• | LH rear door module (LRDM) |
• | RH rear door module (RRDM) |
• | Driver door switch assembly (DDSA) |
• | RH front power window switch |
• | LH rear power window switch |
• | RH rear power window switch |
• | LH front power window motor |
• | RH front power window motor |
• | LH rear power window motor |
• | RH rear power window motor |
• | Class 2 serial data link |
• | DR MOD PWR C/B 30 Amp circuit breaker |
• | DRIVER DR MOD 10 Amp fuse -- DDSA and DDM logic, DDM internal driver
operation. |
• | PSGR DR MOD 10 Amp fuse -- PDM logic and internal driver operation. |
• | REAR DR MOD 15 Amp fuse -- LRDM and RRDM logic and internal driver
operation. |
Power Windows Operation
The vehicle is equipped with power windows controlled by the door modules.
Each passenger door window can be operated, either from a power window switch built
into the driver door switch assembly (DDSA) , or, from a power window switch mounted
locally on its associated door. The driver door window can be operated only from the
driver door power window switch built into the DDSA.
When the driver door module (DDM) receives a driver door window switch request
from the DDSA, the DDM examines the request and inspects to see if it has received
any messages from any of the other vehicle modules prohibiting the movement. If
no prohibitive messages have been received, the DDM then applies power and ground
to the driver door window motor to move the window as requested.
When a passenger door module, passenger front door module (PDM), LH rear door
module (LRDM), or RH rear door module (RRDM), receives a window switch request from,
either the DDSA or the window switch mounted locally to its door, the passenger door
module examines the request and inspects to see if it has received any messages from
any of the other vehicle modules prohibiting the movement. If no prohibitive messages
have been received, the passenger door module then applies power and ground to its
associated window motor to move the window as requested.
Door Modules Power and Ground
For power up, each door module has a separate battery voltage circuit fed by
the rear fuse block, and, one or more separate ground circuits connected to a ground
stake. These voltage and ground circuits are in the C3 harness connector of each
door module and are also used for power window switch and express up sensors, and
for power outside rearview mirror and door lock operations. Door modules power and
ground, as it applies to mirrors and locks, is discussed in the applicable mirrors
and locks description and operations sections.
Door modules battery voltage is supplied as follows:
• | The DDM battery positive voltage circuit is fed by the DRIVER DR MOD
10 amp fuse in the rear fuse block. |
• | The PDM battery positive voltage circuit is fed by the PSGR DR MOD 10
amp fuse in the rear fuse block. |
• | The LRDM and RRDM also have separate battery voltage circuits, but they
are both fed by the REAR DR MOD 15 amp fuse. |
These voltage and ground circuits must not be confused with the power and ground
circuits used exclusively to drive the power window motors, which are discussed in
the following paragraph.
Window Motors Power and Ground
Each door module has a separate battery voltage supply circuit used exclusively
for power window motor operation. However, these individual circuits are spliced
into one circuit, which is fed by the DR MOD PWR C/B circuit breaker located in the
rear fuse block. Each door module also has a separate ground circuit, connected to
a ground stake, and 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. These power
and ground supply circuits are in the C1 harness connector of each door module.
Passenger Door Window Switches
Each passenger door has a power window switch mounted to it. The passenger door
modules, PDM, LRDM, and RRDM, each supply battery voltage and ground to their associated
power window switch. There are 3 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
to ground, and voltage flows through the switch, providing the associated door module
with the necessary signal.
Driver Door Switch Assembly (DDSA)
The driver door switch assembly (DDSA) receives power and ground, through separate
circuits, from the driver door module (DDM). The DDSA contains the only power window
switch for the driver door window, however, it also contains a window switch for
each of the vehicles passenger doors. These switches differ from the individual power
window switches mounted locally to each passenger door in that, the DDSA powers them
internally. When a power window switch on the DDSA is operated, the normally open
switch contacts for that function are closed, and battery voltage flows through the
switch. The DDSA interprets the switch signal, and then sends the appropriate request
message, via the class 2 serial data link, to the appropriate door module to operate
the window.
Window Motors
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.
Windows Express Down Feature
All of the windows have the Express Down feature. This allows the window to
be fully opened by momentarily pressing the window switch to the second detente of
the Down position. Any passenger door window can be expressed down from, either the
appropriate window switch built into the DDSA , or from the window switch mounted
to the associated passenger door. When either switch is operated to Express Down,
both the Down contacts and the Express contacts of the switch being used are closed
to ground and the 2 contact signal is interpreted as an Express Down request. If
the window is operated from a passenger door window switch, the door module associated
with the switch interprets the 2 contact signal. If the window is operated from
the driver door, it is the DDSA that interprets the 2 contact switch signal.
Windows Express Up Feature
The driver door and the front passenger door have the Express Up feature. This
allows the front door windows to be fully closed by momentarily pressing the window
switch to the second detente of the Up position. However, because of safety concerns,
the windows Express Up system is more complicated than the Express Down system. The
Express Up system has been designed to detect when an object has become trapped between
the window glass and the window frame, and to take the appropriate action when such
an event occurs. The Express Up feature is controlled by the front door modules and
the window motor sensors.
Each of the front door window motors has a window sensor mounted to it. The
window sensors determine if there is an obstruction to the travel of its window glass
by detecting differences in their respective window motors electrical pulses. If one
of the sensors detects that a passenger, or other obstacle, has become trapped between
the window glass and the window frame, it sends this information, via 2 communication
circuits, to its associated door module. The door module then reverses the direction
of window travel and disables the Express Up function.
Each front door module and corresponding sensor are wired to each other by 4
separate circuits. These are, the window sensor battery voltage circuit, the window
sensor low reference circuit, the power window high speed serial data circuit, and
the power window low speed serial data circuit. Each front door module supplies battery
voltage, via the window sensor battery voltage circuit, and ground, via the window
sensor low reference circuit, to the sensor. Each door module communicates with its
sensor via the other 2 separate and unique communication circuits. The power window
high speed serial data circuit is a one-way communications line from the sensor to
the module. The power window low speed serial data circuit is a 2-way communications
line that carries information both ways, from the sensor to the module, and, from
the module to the sensor. State-of-health messages, the position of the window glass
in relationship to the distance traveled by the window, and the direction in which
the window is moving are communicated via these circuits.
Either front door window can be expressed up from the appropriate window switch
built into the DDSA . The front passenger door window can also be expressed up from
the window switch mounted to the front passenger door. When either switch is operated
to Express Up for either front door window, both the Up contacts and the Express
contacts of the switch being used are closed to ground. When the front passenger
door window switch is used, the front passenger door module interprets the 2 contact
signal. When the window switch built into the DDSA is used, it is the DDSA that interprets
the 2 contact switch signal.
If a front door module loses 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. This can be done by operating the switch of the
affected window in the Express Up mode until it is in the full Up position. The switch
must be held in the Express Up position for 3-5 seconds after the window has
stopped moving. For more information about programming the Express Up function, refer
to
Window Motor Programming - Express Function
.
Rear Window Lockout Feature
The rear window lockout switch is built into, and receives power and ground
from, the driver door switch assembly (DDSA). There are no external circuits. The
lockout function is used to prevent the passenger door windows from being operated
from their locally mounted switches. When the lockout switch is pressed momentarily,
the switch contacts are briefly closed, the LED indicator on the switch button is
illuminated, and the DDSA processes this switch signal. The DDSA sends the switch
status, via class 2 serial data message, to the passenger door modules. The passenger
door modules then prohibit the windows from being operated from the locally mounted
passenger door window switches. When the lockout function has been activated, the
passenger door windows can still be operated from the driver door by using the window
switches built into the DDSA.