Fixed and Moveable Windows 2-11
Description and Operation
Power Windows Description and
Operation
Power Windows System Components
The power window system consists of the following
components:
• Driver front side door window control switch
• Passenger front side door window control switch
• Left rear side door window switch
• Right rear side door window switch
• Window motors in each of the doors
• Body control module (BCM)
Driver and Passenger Express Up and
Express Down Power Window Motors
The driver and passenger doors contains a window
motor is smart motor that will detect excessive
resistance while performing the express up function
and automatically reverse direction to prevent injury to
any occupants that may become trapped between the
closing window and the door frame. The automatic
reverse safety feature can be overridden by pulling and
holding the window switch.
The logic circuit within the window motor monitors the
up, down and express signal circuits which are
normally equal to B+ voltage. When a switch is used on
the front side door window control switch, the contacts
close causing a voltage drop within the appropriate
signal circuit. The window motor will detect the voltage
drop and will command the window to move in the
direction requested.
The driver front side door window control switch
communicates to the BCM by a serial data circuit.
When the driver wishes to control the passenger
window, the driver will use the appropriate switch on the
driver front side door window control switch. When this
switch is used, a serial data messag e is sent to the
BCM requesting the passenger window motor
command, the BCM will then send a serial data
message to the passenger window motor which will
then move in the direction requested.
Left Rear, Right Rear Express Down
Window Motors
For the right rear and left rear doors, when their window
switch is pressed in the down position, battery positive
voltage is applied to their respective window motor
control circuit and ground to the other window motor
control circuit causing that window to open. When the
individual window switch is pulled in the up position,
voltage and ground is applied to the window motor in
the opposite direction causing that window to close.
The return path to ground is supplied through the
inactive control circuit being normally grounded through
the window switch.
Each rear side door window switch communicates to
the BCM by a serial data circuit. When the driver
wishes to control the left rear or right rear window, the
driver will use the appropriate switch on the driver front
side door window control switch. When this switch is
used, a serial data message is sent to the BCM
requesting a window motor command, the BCM will
then send a serial data message to the appropria te rear
side door window switch which will then command that
window to move in the direction requested.
Lockout Switch Feature
The driver front side door window control switch
contains a window lockout switch, when the driver
presses the window lockout switch, a serial data
message is sent to the BCM which will send a disable
command to the rear side door window switches,
deactivating them. The rear windows will still function
normally from the switches on the driver front side door
window control switch.
Rear Window Defogger Description
and Operation
Rear Window Defogger System
Components
The rear window defogger system consists of the
following components:
• Body Control Module
• Front Heater and Air Conditioning User Interface
Control
• Rear Body Wiring Harness Junction Block
(Contains PCB Rear Defogger Relay
• Rear Defogger Grid
• 40A Fuse
Rear Window Defogger Operation
The rear defog control system utilizes a single zone
backlight design, driven with a single relay
configuration. A switch for the customer to control the
system is provided within the front heater and air
conditioning user interface control. Also included in the
front heater and air conditioning user interface control
is an indicator to inform the customer with the current
state of the system. The system is only operational
when engine is running or during remote start.
Pressing the heated rear window switch causes the
front heater and air conditioning user interface control
to send a serial data message to the body control
module requesting rear window defog operation. The
body control module upon receipt of the serial data
message will provide voltage to the coil side of the rear
defogger relay, this will energize the relay causing the
relay switch contacts to close allowing B+ voltage to
flow through the rear defogger grid control circuit to the
rear defogger grid.
When the rear heated rear window switch is pressed
and the engine is running, the rear window defogger
grid will activate and will turn off automatical ly
depending upon the vehicle speed (refer to owner’s
manual for rear window defogger operation cycles)
2022 - Silverado 1500 (New) Electrical Body Builder Manual
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