Hummer H3. Manual — part 38

oxidation that may be present on the bolt.

Even new bolts contain a protective coating that may insulate or cause a resistance in the
test circuit.

If correct connections to the battery terminal bolts in the vehicle are in doubt, perform the
following steps:

1. Disconnect the negative battery cable.

2. Disconnect the positive battery cable.

3. Install the test adapters on the terminals.

4. Follow the instructions for testing a removed battery.

If the tester displays a REPLACE BATTERY or BAD CELL-REPLACE result for a
battery tested in the vehicle with the battery cables connected, perform the following steps:

1. Disconnect the negative battery cable.

2. Disconnect the positive battery cable.

3. Install the tester adapters.

4. Follow the instructions for testing a removed battery.

5. Replace the battery only if the second test shows a REPLACE BATTERY or BAD

CELL-REPLACE result.

Use the test code from the second test for any warranty purposes.

Use the correct terminal adapters.

Do not use any common bolts or a combination of bolts, of nuts, and of washers as adapters
when testing the battery.

Use the test adapters that are provided with the J 42000 or GM P/N 12303040 terminal
adapters. See Special Tools. If the adapters that are provided with the J 42000 require

IMPORTANT: Always write the test code displayed by the tester on the

repair order for any warranty purposes. The number is a
unique code that describes the test data for a particular
battery at a particular time. The test code may
occasionally repeat when you retest the same battery.
More often, each test will result in a different code. Use
the test code from the second, or Out of Vehicle test.

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replacement, use GM P/N 12303040. See Special Tools. Any other adapter may not
contact the correct areas of the battery terminal, causing a resistance that may result in an
invalid battery test result.

Circuit/System Testing

1. Inspect the battery for a cracked, broken, or damaged case, which may be indicated by

battery acid leakage.

If there is any apparent damage, replace the battery.

2. Verify the cold cranking amperage (CCA), and reserve capacity (RC) and/or amp hour

(AH) rating of the battery to the original battery or original equipment (OE) specification.
Refer to Battery Usage.

If the battery does not meet or exceed specifications, replace the battery.

3. Verify that the battery cables are clean and tight. The battery terminal bolts should be

torqued as specified in Fastener Tightening Specifications.

If the battery cable(s) need to be cleaned, clean as required and tighten as specified.

If the battery cable(s) are damaged, replace then tighten as specified.

4. Install the J 42000 and follow directions supplied by the tester. See Special Tools.

If the tester calls for charging the battery, refer to Battery Charging.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Battery Positive and Negative Cable Replacement (LLR)

Battery Replacement (LH8) or Battery Replacement (LLR)

BATTERY CHARGING

Special Tools

CAUTION: Unless directed otherwise, the ignition and start switch must

be in the OFF or LOCK position, and all electrical loads must
be OFF before servicing any electrical component. Disconnect
the negative battery cable to prevent an electrical spark
should a tool or equipment come in contact with an exposed
electrical terminal. Failure to follow these precautions may
result in personal injury and/or damage to the vehicle or its
components.

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J 42000 Battery Tester. See Special Tools.

Charging

For best results, use an automatic taper-rate battery charger with a voltage capability of 16
volts.

The charging area should be well ventilated.

Do not charge a battery that appears to be frozen. Allow the battery to warm to room
temperature and test it using the J 42000 before charging. See Special Tools.

Battery State of Charge

The maintenance-free batteries SOC is estimated by reading the voltage of the battery across the
battery terminals. Because the voltage is affected by current flow into or out of the battery, the
engine must be stopped and all electrical loads turned OFF, including parasitic loads, when
checking the voltage. The voltage can also be affected if the battery has just been charged or
discharged, so it is important to consider what has happened to the battery in the time just before
testing. Use the following procedure to determine the batteries SOC:

1. Be sure all electrical loads are turned OFF.

2. Determine whether the battery has been used in a vehicle or charged within the past 12

hours.

If the answer is no, the terminal voltage will be stabilized and no action is necessary
before reading the voltage. Skip to step 3.

If the answer is yes, terminal voltage will not be stabilized and you should wait 12
hours since the last time the battery was used.

3. Estimate the battery temperature by determining the average temperature to which the

battery has been exposed for the past 12 hours.

4. Measure the battery voltage at the battery terminals. Refer to the following table to

IMPORTANT: Using voltage to determine the batteries state of charge (SOC) is

only accurate after the battery has been at rest for 24 hours. This
is enough time for the acid in each cell to equalize. If the battery
has been charged or discharged in the past 24 hours, the battery
SOC will only be an estimate.

IMPORTANT: The table is accurate to 10 percent only after the battery has

been at rest for 12 hours.

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determine the SOC according to the estimated battery temperature:

Use the SOC information as follows:

A battery with a SOC that is below 65 percent must always be recharged before returning it
to service or continuing storage.

A battery with a SOC that is 65 percent or greater is generally considered to be charged
enough in order to be returned to normal service or in order to continue storage. However,
if the battery is being used in slow traffic or with short drive times, or if the temperature is
very hot or very cold, the battery should be fully charged, to at least 90 percent, before
returning it to service or continuing storage.

Charging Time Required

The time required to charge a battery will vary depending upon the following factors:

The battery charger capacity-The higher the charger amperage, the less time it will take to
charge the battery.

The SOC of the battery-A completely discharged battery requires more than twice as much
charging time as a half charged battery. In a discharged battery with a voltage below 11
volts, the battery has a very high internal resistance and may only accept a very low current
at first. Later, as the charging current causes the acid content to increase in the electrolyte,
the charging current will increase. Extremely discharged batteries may not activate the
reversed voltage protection in some chargers. Refer to the manufacturer's instructions for
operating this circuitry.

The temperature of the battery-The colder the battery is, the more time it takes to recharge
the battery. The charging current accepted by a cold battery is very low at first. As the
battery warms, the charging current will increase.

Charging Procedure

Battery Voltage

% Charge at 0°C (32°F)

% Charge at 25°C (75°F)

12.75 V

100%

100%

12.7 V

100%

90%

12.6 V

90%

75%

12.45 V

75%

65%

12.2 V

65%

45%

12.0 V

40%

20%

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2008 ENGINE Engine Electrical - H3