Hummer H2. Manual — part 556

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The liftgate ajar switch

Driver Door Ajar And Passenger Door Ajar

The DDM and PDM receive a discrete input from the respective door ajar switch to indicate the status of the
door. The DDM or PDM then communicates this status to the IPC via class 2 message. The IPC, upon receipt of
this class 2 message, will illuminate the appropriate door ajar message in the DIC and also send a class 2
message to the radio to activate the door ajar audible warning when the following conditions are met:

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The transmission is removed from PARK

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The vehicle speed is greater then 8.05 km/h (5 mph)

Left Rear Door Ajar And Right Rear Door Ajar

The BCM receives a discrete inputs from both the left and right rear door and liftgate ajar switches to indicate
the status of the doors and liftgate. The BCM then communicates this status to the IPC via class 2 message. The
IPC, upon receipt of this class 2 message, will illuminate the appropriate door ajar message in the DIC and also
send a class 2 message to the radio to activate the door ajar audible warning when the following conditions are
met:

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The transmission is removed from PARK

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The vehicle speed is greater then 8.05 km/h (5 mph)

OUTSIDE MIRROR DESCRIPTION AND OPERATION (POWER MIRRORS)

Power Mirror System

Power Mirror System Components

The power mirror system consists of the following components:

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The driver door module - Class 2 module with integrated switches and requires programming when
replaced

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The passenger door module - Class 2 module with integrated switches, requires programming when
replaced and also contains the RFA receiver

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The power mirror direction switch - Integrated into DDM and is a 4 position momentary switch that
provides a signal input to the DDM for up, down, left/extend and right/retract with a mirror switch
activation

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The mirror select switch - Integrated into DDM and is a 3 position switch that allows the operator to
select the left or right mirror and also a neutral/fold position

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The left outside power mirror - Contains both the vertical and horizontal mirror motors and is serviced as
a complete mirror assembly

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The right outside power mirror - Contains both the vertical and horizontal mirror motors and is serviced
as a complete mirror assembly

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The body control module - Class 2 module that requires programming when replaced, serves as the power

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Doors - Hummer H2

mode master and is the main message handler

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The DDM 10A fuse - Located in the I/P fuse block and is hot at all times

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The PDM 10A fuse - Located in the I/P fuse block and is hot at all times

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The memory switch, if equipped with memory mirrors - Supplied power by the DDM and provides a
voltage signal to the DDM upon a switch activation

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The horizontal and vertical position sensors, if equipped with memory mirrors - Supplied a 5 volt and low
reference by the DDM/PDM and provide a variable voltage signal to the DDM/PDM that is proportional
to mirror position

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The park neutral position switch, if equipped with memory mirrors - Provides transmission gear selection
information to the PCM and is used for memory recall and mirror tilt in reverse functions

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The powertrain control module, if equipped with memory mirrors - Class 2 module that requires
programming when replaced and provides Class 2 message indicating transmission gear selection

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The driver Information Center (DIC), if equipped with memory mirrors - Part of the instrument cluster
which is a Class 2 module that requires programming when replaced and is used to personalize the
memory recall and mirror tilt in reverse functions

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Fold motor in each of the outside mirrors, if equipped with power fold mirrors - Provides extend and
retract movements of the mirror and is serviced as a complete mirror assembly

Each of the outside power mirrors contains 2 reversible motors to provide horizontal and vertical movement of
the mirror glass. The vertical motor operates the up and down directions and the horizontal motor operates the
left and right directions. If equipped with power folding mirrors, each outside power mirror will contain a
reversible fold motor to operate the extend and retract functions. Each of the mirror motors are circuit breaker
protected.

Power Mirror System Controls

The power mirror switch incorporates a 3 position mirror select switch and a 4 position mirror direction switch.
The mirror select switch allows the operator to select the mirror to be moved by selecting the L position for the
left power mirror, selecting the R position for the right power mirror or the center which is the neutral/fold
position. The mirror direction switch is a 4 position switch that allows the operator to move the selected mirror
up, down, left or right. The mirror direction switch also functions as the folding mirror switch. When the
selector switch is in the neutral/fold position, activate the mirror direction switch to the left to extend the
mirrors and right to retract the mirrors.

Power Mirror System Operation

The power mirror switch is integrated into the DDM. The left and right mirror positions of the select switch and
4 positions of the direction switch, when active, will provide a signal to the DDM. If the selector switch is
placed in the L position and the up switch is depressed, 2 signals will be supplied to the DDM. The DDM upon
receipt of these signals will provide battery voltage to the mirror motor left/up control circuit and ground to the
mirror motor down control circuit and the mirror will move up. The remainder of the driver mirror functions
operate in the same manner as described above except the DDM will supply battery voltage and ground to the
appropriate control circuits for the direction selected. If the passenger mirror is selected and a direction switch is
activated, the DDM sends a class 2 message to the PDM indicating that the passenger mirror was selected and
the direction to be commanded. The PDM will then supply battery voltage and ground to the appropriate control

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2004 ACCESSORIES & EQUIPMENT Doors - Hummer H2

circuits for the direction selected.

Memory Mirror System

Memory Mirror System Controls

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The DDM and PDM are capable of storing mirror positions and controlling the mirrors to these positions to the
preferred settings of 2 different drivers. Each driver will be able to personalize the memory system by
positioning the mirrors and seats to their preferred settings. Then press and hold the memory 1 or memory 2
button until an audible chime is heard and the current mirror positions will be stored into memory of the DDM
and PDM. Seat position will be stored in the Driver Seat Module (DSM). Once the mirror and seat positions
have been stored into memory, a momentary memory 1 or memory 2 switch activation will supply the DDM a
battery voltage signal. The DDM, upon receipt of the memory switch signal, with the transmission in park or
neutral, will then drive the driver mirror to the corresponding stored memory position. The DDM will also send
a class 2 message to the PDM and DSM indicating that a memory switch activation occurred. The PDM will
then drive the passenger mirror and the DSM will drive the driver seat to the corresponding stored memory
position. The memory system can also be controlled by any of the following if programmed using the Driver
Information Center (DIC) to enable/disable the features:

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Auto exit/entry seat positioning

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Mirror and seat position recall on a keyless entry unlock activation

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Mirror and seat position recall on ignition key insertion

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Mirror tilt in reverse

For further information on programming and configuration, refer to Driver Personalization in Personalization.

Memory Mirror System Operation

Mirror position is determined by both horizontal and vertical position sensors in each of the power mirrors. The
DDM and PDM supplies a reference voltage and a low reference to these sensors and determines mirror
position through the horizontal and vertical position signal circuits.

The memory switch receives power from the DDM through the battery supply voltage circuit and the DDM
fuse. The DDM upon receipt of a memory switch signal input or an appropriate class 2 message from the BCM,
the DDM and PDM will then supply battery voltage and ground to the appropriate power mirror motors through
the mirror motor control circuits to move the mirrors to the predetermined positions.

Mirror Tilt in Reverse Controls

This feature is capable of tilting the left, right or both power mirrors when the transmission is placed in reverse
to provide enhanced visibility during parking or backing maneuvers and is programmable through the Driver
Information Center. This feature can be personalized to the needs of 2 different drivers. For further information,
refer to Driver Personalization in Personalization.

Mirror Tilt in Reverse Operation

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When the vehicle is placed in reverse and the appropriate class 2 message from the BCM is received by the
DDM and PDM, the DDM and PDM will then supply battery voltage and ground to the appropriate power
mirror motors through the mirror motor control circuits to move the mirrors to the predetermined positions. The
positions that are stored can be altered by starting the engine, applying the brake, placing the vehicle in reverse
and controlling both the left and right mirrors the desired positions and shifting the vehicle out of reverse. These
new positions will be stored for the last memory recall that happened.

Folding Mirror System

Folding Mirror System Controls

The folding mirror system requires signals from 2 separate switches. The mirror select switch must be in the
neutral/fold position and the mirror direction switch must be activated to the left/extend or right/retract
positions. Both switches are integrated into the DDM and provide direct signals.

Folding Mirror System Operation

Upon receipt of the required switch inputs the DDM will supply battery voltage and ground to the mirror fold
motor control circuits to perform the requested extend or retract function. The DDM will also send a class 2
message to the PDM indicating the requested function. The PDM will supply battery voltage and ground to the
mirror fold motor control circuits to perform the requested extend or retract function.

OUTSIDE MIRROR DESCRIPTION AND OPERATION (HEATED MIRRORS)

Heated OSRV Mirror

On vehicles equipped with heated OSRV mirrors, the DDM and PDM controls the activation of the mirror
heaters. Upon receiving a Class 2 message indicating a request for heated mirrors, the DDM, and PDM for the
passenger side, will activate the mirror heater output. The mirror heaters will remain active until a new message
is received indicating rear defogger is to be deactivated, either by driver input or by expiration of a calibrated
timer.

OUTSIDE MIRROR DESCRIPTION AND OPERATION (AUTO DAY - NIGHT MIRRORS)

Mirrors - Outside Automatic Day/Night Feature

The automatic day/night feature of the driver outside rearview mirror is controlled by the inside rearview
mirror. The inside rearview mirror supplies a signal and a low reference to the driver outside rearview mirror.
The voltage on the signal circuit of the driver outside rearview mirror varies between 0.5 to 1.5 volts depending
on light conditions present at the inside rearview mirror. At night, with the automatic day-night feature enabled,
the driver outside rearview mirror will automatically darken with the inside rearview mirror to reduce the glare
from the headlamps from behind. The voltage on the signal circuit of the driver outside rearview mirror will be
near 1.5 volts. In the daytime, the mirrors are in a normal state. The voltage on the signal circuit of the driver
outside rearview mirror may be less than or near 0.5 volts. Refer to Automatic Day-Night Mirror Description
and Operation in Stationary Windows for further description and operation of the inside rearview mirror.

SPECIAL TOOLS AND EQUIPMENT

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