Description And Operation; Door Ajar Indicator Description And Operation; Hood Ajar Indicator Description And Operation; Power Door Locks Description And Operation - Chevrolet Silverado 4500HD Manual

Description and Operation

Door Ajar Indicator Description and
Operation
Door Ajar Indicator System
Components
The door ajar indicator system consists of the following
components:
Body control module
Instrument cluster
Driver door latch
Passenger door latch
Left rear door latch
Right rear door latch
Driver window motor (A31)
Passenger window switch (A31)
Left rear window switch ( A31)
Right rear window switch (A31)
Door Ajar System
Depending upon if the vehicle is a standard cab,
extended cab or crew cab and/or is equipped with
power windows or without power windows affects how
the driver and passenger door ajar signal circuits are
configured and monitored.
Driver Door Ajar (With A31)
The driver window motor will provide a 12V signal to the
driver door ajar switch within the door latch to indicate
the status of the door. When the driver door is open, the
contract within the ajar switch closes providing a
ground part for the signal circuit. The driver window
motor will detect the voltage drop in the ajar signal
circuit and will send a serial data message to the body
control module. The body control module will then send
a message to the instrument cluster which will
illuminate the door ajar icon.
Passenger and Rear Doors Ajar
(With A31)
The passenger and rear window switches provide a
12V signal to the respective door ajar switch within the
door latch to indicate the status of the door. When the
door is open, the contract within the ajar switch closes
providing a ground part for the signal circuit. The
window switch will detect the voltage drop in the ajar
signal circuit and will send a serial data message to the
body control module. The body control module will then
send a message to the instrument cluster which will
illuminate the door ajar icon.
Driver, Passenger and Rear Doors Ajar
(Without A31)
The body control module provides a 12V signal to each
door ajar switch within the door latch to indicate the
status of the door. When the door is open, the contract
within the ajar switch closes providing a ground part for
the signal circuit. The body control module will detect
the voltage drop in the ajar signal circuit and will send a
message to the instrument cluster which will illuminate
the door ajar icon
2021 - Silverado 4500HD, 5500HD, and 6500HD Electrical Body Builder Manual
Hood Ajar Indicator Description and
Operation
Hood Ajar Switch
The body control module (BCM) applies B+ to the hood
ajar signal circuit and monitors the voltage to determine
the position of the hood. When the hood is closed, the
switch is open and voltage remains high. When the
hood is open, the switch is closed and the voltage is
pulled low.
The BCM uses the hood ajar switch as a content theft
deterrent alarm trigger.
Hood Ajar Indicator/Message
When the hood is ajar, a message is displayed on the
DIC or the hood ajar indicator will be illuminated.
Power Door Locks Description and
Operation
Door Lock System Components
The power door lock system consists of the following
components:
Driver door lock switch
Child door lockout switch (Part of the driver
window switch)
Passenger door lock switch
Front door lock actuators
Rear door lock actuators (Extended and crew
cab models)
Body control module (BCM)
Keyless entry control module
Keyless entry transmitter
Right instrument panel fuse block (Contains child
security lock disable PCB relay)
Vehicle Access 2-63