Hummer H2. Manual — part 607

This vehicle is only available with full function 8 way power seats with driver memory. For the driver memory
seat operation refer to Memory Seats Description and Operation . The passenger power seat is completely
controlled through the power seat switch. Battery voltage is supplied to the power seat switch through the
power seat circuit breaker. While the seat adjuster switches are in an inactive state the switch contacts are
closed to the power seat switch ground circuit. When a power seat switch is pressed to an active state the switch
contact is closed to the battery voltage supply circuit. Each seat adjuster motor is controlled by the power seat
switch through 2 motor control circuits. The seat adjuster motors are bidirectional and the direction of adjuster
motor rotation is determined by which of the adjuster motor control circuits is switched to battery voltage while
the other remains grounded.

LUMBAR SUPPORT DESCRIPTION AND OPERATION

Lumbar Support/Torso Bolster System Components

The lumbar support/torso bolster system for the driver and passenger consists of the following components:

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Driver and passenger lumbar support/torso bolster switches

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Driver and passenger lumbar support/torso bolster motor assemblies

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Driver seat module

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Memory select switch

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Driver door module

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SEAT 30A circuit breaker

Lumbar Support/Torso Bolster System Operation

The driver seat lumbar and torso adjuster motors are controlled through the driver seat module, while the
passenger seat lumbar and torso adjuster motors are controlled directly through the lumbar support/torso bolster
adjuster switch.

The driver seat module supplies the driver seat lumbar support/torso bolster adjuster switch assembly with a
battery positive reference voltage. While the switches are in an inactive state the switch contacts are closed to
the switch ground circuit. When a switch is pressed to an active state the switch contact is closed to the
reference voltage circuit. Battery voltage on a switch signal circuit indicates to the driver seat module the switch
status is active. Each seat adjuster motor is controlled by the driver seat module through 2 motor control
circuits. While the seat adjuster motors are in an inactive state the motor control circuits are closed to ground
circuit contacts within the driver seat module. The driver seat module operates the seat adjuster motors by
switching one of a motor's control circuits to battery voltage. The seat adjuster motors are bidirectional and the
direction of adjuster motor rotation is determined by which of the adjuster motor control circuits is switched to
battery voltage while the other remains grounded.

The seat adjuster motors are equipped with internal position sensors. The adjuster motor position sensors are
monitored by the driver seat module and are used to determine the seat position when storing or recalling
memory settings. The lumbar and torso adjuster motors use hall effect type position sensors. The hall effect
position sensors are supplied with battery positive reference and ground circuits from the driver seat module.
The position sensor signal circuits are supplied battery positive voltage through a resistor them monitored
within the driver seat module. During adjuster motor operation the hall effect position sensor provides a single

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Seats - Hummer H2

pulse for every revolution of the adjuster motor shaft. The driver seat module counts the pulses from the
position sensor signal circuits to determine the adjuster motor positions when storing or recalling memory seat
position settings.

Battery voltage is supplied to the passenger seat lumbar support/torso bolster switch through the SEAT 30A
circuit breaker. While the switches are in an inactive state the switch contacts are closed to the switch ground
circuit. When a switch is pressed to an active state the switch contact is closed to the battery voltage supply
circuit. Each motor is controlled by the power seat switch through 2 motor control circuits. The motors are
bidirectional and the direction of motor rotation is determined by which of the motor control circuits is switched
to battery voltage while the other remains grounded.

HEATED SEATS DESCRIPTION AND OPERATION (FRONT)

Heated Seat Components

The heated seat system consists of the following components:

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Driver and passenger heated seat switches

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Driver and passenger seat back heater elements

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Driver and passenger seat cushion heater elements

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Driver and passenger seat back temperature sensors

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Driver seat module

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Driver door module

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Passenger door module

Heated Seat System Operation

The driver and passenger heated seats have 2 heat zone operating modes with 3 heat level modes and will
operate only while the engine is running. The heat zones are determined by which of the 2 heated seat buttons
are pressed, while the heat level is determined by the number of times they are pressed. Pressing the seat
cushion button 1 time will activate the seat back and cushion heater elements in the high mode. Each time the
seat cushion button is pressed the seat back and cushion heat level is reduced from high to medium, low, and
off. Pressing the heated seat back button 1 time will activate only the seat back heater element in the high mode.
Each time the seat back button is pressed the seat back heat level is reduced from high to medium, low, and off.
During heated seat operation the heat zone operating mode may be changed without affecting the current heat
level mode.

The heated seat switches are momentary contact switches and are inputs to the driver and passenger door
modules. Battery voltage is supplied to the switch assembly from the door module, and when a heated seat
switch is pressed and released a brief switch signal voltage is supplied to the door module. Whenever the door
module receives an active heated seat switch input, the next heated seat operating mode is determined by
whatever the current mode may be. The seat heater elements are controlled by the driver seat module using
inputs from the door modules through Class 2 serial data circuit messages. The driver seat module controls the
voltage supply and the ground circuits to the seat heater elements. When a heated seat function is commanded
active, the seat module will switch battery voltage to the heater element supply circuits, and ground is provided
through low side drive control circuits. During heated seat operation both the seat back and cushion heater

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Seats - Hummer H2

elements are supplied battery voltage. The seat module grounds the appropriate control circuits for back only or
back and cushion heating modes, and opens or closes the active control circuits as necessary in order to
maintain the desired seat temperature. The seat module relies on inputs from thermistors located in the driver
and passenger seat backs to control heated seat temperatures. The thermistors are 2 wire sensors supplied with a
5-volt referenced signal circuit and a low reference circuit from the seat module. Resistance through the
thermistors varies with temperature causing the heated seat sensor signal circuit voltage levels to decrease as the
seat back temperatures rise. The seat modules allow heated seat operation only while the engine is running
which is determined by a Class 2 serial data circuit message from the powertrain control module.

HEATED SEATS DESCRIPTION AND OPERATION (REAR)

Rear Heated Seat Components

The rear heated seat system consists of the following components:

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Left and right seat cushion heater elements

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Left and right heated seat control modules

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Left and right heated seat switches

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IGN 3 10A fuse

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SEO B1 15A fuse

Rear Heated Seat Operation

The rear heated seat system will heat the rear seat cushions in high or low heat modes. Battery voltage to the
seat cushion heater elements is controlled by the heated seat control modules using inputs from the heated seat
switches and the seat cushion temperature sensors. The heated seat switch signal circuit is supplied with a
reference voltage through a resistor and monitored within the control module. The heated seat switch is a
momentary contact type and when activated the signal circuit is briefly closed to ground. Whenever the control
module receives an active switch input, the heated seat operating mode is determined by whatever the current
mode may be, from off to high then low. The control module monitors the seat cushion temperature by sending
a signal voltage through a thermistor located in the heater element pad. The control module cycles the battery
voltage circuit to the heater element as necessary in order to maintain the desired seat cushion temperature.

MEMORY SEATS DESCRIPTION AND OPERATION

Memory Seat System Components

The memory seat system consists of the following components:

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Power seat switch assembly

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Memory recall switch assembly

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Horizontal adjuster motor

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Front vertical adjuster motor

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Rear vertical adjuster motor

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Recline adjuster motor

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Seats - Hummer H2

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Driver seat module

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Driver door module

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SEAT 30A circuit breaker

Memory Seat System Description

Battery voltage is supplied to the driver seat module through the power seat circuit breaker. The driver seat
module supplies the seat adjuster switch assembly with a battery positive reference voltage. While the seat
adjuster switches are in an inactive state the switch contacts are closed to the adjuster switch ground circuit.
When a seat adjuster switch is pressed to an active state the switch contact is closed to the reference voltage
circuit. Battery voltage on a switch signal circuit indicates to the driver seat module the switch status is active.
Each seat adjuster motor is controlled by the driver seat module through 2 motor control circuits. While the seat
adjuster motors are in an inactive state the motor control circuits are closed to ground circuit contacts within the
driver seat module. The driver seat module operates the seat adjuster motors by switching one of a motor's
control circuits to battery voltage. The seat adjuster motors are bidirectional and the direction of adjuster motor
rotation is determined by which of the adjuster motor control circuits is switched to battery voltage while the
other remains grounded.

Memory Set/Recall Operation

The seat adjuster motors are equipped with internal position sensors. The adjuster motor position sensors are
monitored by the driver seat module and are used to determine the seat position when storing or recalling
memory settings. The horizontal, front vertical, and rear vertical adjuster motors use hall effect type position
sensors. The hall effect position sensors are supplied with battery positive reference and ground circuits from
the driver seat module. The position sensor signal circuits are supplied battery positive voltage through a
resistor them monitored within the driver seat module. During adjuster motor operation the hall effect position
sensor provides a single pulse for every revolution of the adjuster motor shaft. The driver seat module counts
the pulses from the position sensor signal circuits to determine the adjuster motor positions when storing or
recalling memory seat position settings. The recline adjuster motor is equipped with a potentiometer type
position sensor. The recline motor position sensor is supplied with it's own 5-volt reference and ground circuits
from the driver seat module. The recline position sensor signal circuit is referenced from ground within the
driver seat module. The signal voltage monitored by the driver seat module ranges from 0.39 - 4.58 volts and is
determined by the wiper location on the resistor within the recline motor position sensor. The recline motor
position sensor signal circuit voltage level is used by the driver seat module to determine the seat recline
position when storing or recalling memory seat position settings.

The memory recall switch assembly on the driver's door provides inputs to the driver door module. Battery
voltage is supplied to the memory recall switch assembly from the driver door module. When a RCL 1, RCL 2,
or EXIT switch is pressed, the switch contacts close the appropriate switch signal circuit to the battery voltage
supply circuit within the memory recall switch assembly. When the driver door module receives active switch
signals from the memory recall switch assembly, the appropriate commands are sent to the driver seat module
using the Class 2 Serial Data circuit.

Memory seat recall operation is allowed only with the transmission selector lever in the PARK position while
the ignition is on. The transmission selector lever position data is provided to the driver seat module by a
message through the Class 2 Serial Data circuit.

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Seats - Hummer H2