Hummer H2. Manual — part 1081

Fig. 15: Underhood Fuse Block Legend - 3 Of 3 (2003)
Courtesy of GENERAL MOTORS CORP.

2004 Hummer H2

2003-04 ELECTRICAL Fuses & Circuit Breakers - H2

Fig. 16: Underhood Fuse Block Legend - 3 Of 3 (2004)
Courtesy of GENERAL MOTORS CORP.

2004 Hummer H2

2003-04 ELECTRICAL Fuses & Circuit Breakers - H2

2003-04 STARTING & CHARGING SYSTEMS

Generators & Regulators - H2

DESCRIPTION & OPERATION

AD-244 generators are non-repairable. They are electrically similar to earlier models. Generator features the
following major components:

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A delta stator.

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Rectifier bridge.

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Rotor with slip rings and brushes.

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Conventional pulley.

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Dual internal fans.

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Voltage regulator.

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Pulley and fan cool slip ring and frame.

AD stands for air-cooled dual internal fan, 2 is an electrical design designator, 30/44 denotes outside diameter
of stator laminations in millimeters, over 100 millimeters. Generator is rated at 145 amperes. Generator features
permanently lubricated bearings. Service should only include tightening of mounting components. Generator is
replaced as a complete unit.

Voltage regulator controls field current of rotor in order to limit system voltage. Regulator switches current on
and off at a rate of 400 cycles per second in order to perform these following functions:

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Radio noise control.

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Obtain correct average current needed for proper system voltage control.

At high speeds, on-time may be 10 percent with off-time at 90 percent. At low speeds, on-time may be 90
percent and off-time 10 percent.

Instrument Panel Cluster (IPC) illuminates charge indicator on Driver's Information Center (DIC) message
center when this occurs:

WARNING:

Vehicles are equipped with air bag supplemental restraint system. Before
attempting any repairs involving steering column, instrument panel or
related components, see AIR BAG DEACTIVATION PROCEDURES in AIR
BAG RESTRAINT SYSTEMS article in RESTRAINTS.

CAUTION: When battery is disconnected, vehicle computer and memory systems

may lose memory data. Driveability problems may exist until computer
systems have completed a relearn cycle. See appropriate COMPUTER
RELEARN PROCEDURES article in GENERAL INFORMATION before
disconnecting battery.

2004 Hummer H2

2003-04 STARTING & CHARGING SYSTEMS Generators & Regulators - H2

2004 Hummer H2

2003-04 STARTING & CHARGING SYSTEMS Generators & Regulators - H2

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Powertrain Control Module (PCM) detects that generator output is 11 volts or less or greater than 16
volts. IPC receives a class 2 message from PCM requesting illumination.

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IPC determines that system voltage is 11 volts or less or greater than 16 volts. IPC receives a class 2
message from Body Control Module (BCM) indicating system voltage.

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IPC performs displays test at start of each ignition cycle. Indicator illuminates for approximately 5
seconds.

COMPONENT LOCATIONS

For component locations, see ELECTRICAL COMPONENT LOCATOR article in ELECTRICAL.

ADJUSTMENTS

BELT ADJUSTMENT

TROUBLE SHOOTING

PRELIMINARY INSPECTION

Verify customer complaint by operating suspected system. Visually inspect for obvious signs of mechanical and
electrical damage. Ensure battery is fully charged and passes load test. See BATTERY TESTING &
INSPECTION under ON-VEHICLE TESTING. Inspect for blown fuses. See COMPONENT LOCATIONS .
Inspect for loose or corroded connections, damaged wiring harnesses and/or switches. Check for a broken or
partially broken wire inside insulation, which could cause system malfunction but prove good in a
continuity/voltage check with system disconnected. Ensure any aftermarket electronic equipment is properly
installed. If fault is found, repair as necessary. If no fault is found, perform self-diagnostics. See SELF
DIAGNOSTIC SYSTEM .

SYSTEM OPERATION CHECK

NOTE:

Drive belt tension is controlled by a belt tensioner. No adjustment is required.
For drive belt routing, see DRIVE BELT ROUTING article in COOLING SYSTEM
SPECIFICATIONS & DRIVE BELT ROUTING - H2 .

NOTE:

For additional information, see CHARGING SYSTEM - GENERAL TROUBLE
SHOOTING article in GENERAL INFORMATION.

NOTE:

Before making electrical checks, visually inspect all terminals for clean, tight
connections. Ensure all charging system related fuses are okay. Check
generator mounting bolts and drive belt tension. Ensure battery is fully charged
and in good condition prior to testing charging system. See BATTERY TESTING
& INSPECTION under ON-VEHICLE TESTING. Ensure battery cable connections
are in good condition and free of corrosion. Ensure starting system is okay. See
STARTERS article in ELECTRICAL.

2004 Hummer H2

2003-04 STARTING & CHARGING SYSTEMS Generators & Regulators - H2