Hummer H3. Manual - part 8

1. Turn OFF the charger.

2. Ensure that all of the battery terminal connections are clean and tight.

3. Connect the charger positive lead to the battery positive terminal on the battery or the

remote jumper stud underhood.

4. Connect the negative charger lead to a solid engine ground or to a ground stud in the engine

compartment that is connected directly to the battery negative terminal, but away from the
battery. If the negative battery cable is disconnected and a terminal adapter is being used,
connect directly to the adapter.

5. Turn ON the charger and set to the highest setting for normal charging.

6. Inspect the battery every half hour after starting the battery charger.

Charge the battery until the taper-rate charger indicates that the battery is fully
charged.

Estimate the battery temperature by feeling the side of the battery. If it feels hot to the
touch or its temperature is over 45°C (125°F), discontinue charging and allow the
battery to cool before resuming charging.

7. After charging, test the battery. Refer to Battery Inspection/Test (Non-HP2).

BATTERY ELECTRICAL DRAIN/PARASITIC LOAD TEST

Tools Required

J 38758 Parasitic Draw Test Switch. See Special Tools.

Diagnostic Aids

Be sure to rule out any possible obvious influences, such as customer error or aftermarket
equipment.

Customer driving habits, such as regular short trips. This does not allow enough time to
properly charge the battery. Refer to Battery Description and Operation.

Verify that the battery and charging system are in proper working order. Refer to Battery
Charging and Charging System Test.

A battery discharging for no apparent reason while the vehicle is parked can be caused by
an intermittent draw, such as a module waking up, or a continuous draw, such as a dome

NOTE:

Do not connect the negative charger lead to the housings of
other vehicle electrical accessories or equipment. The action
of the battery charger may damage such equipment.

2006 Hummer H3

2006 ENGINE Engine Electrical - H3

light or stuck relay.

Some systems and modules such as OnStar®, and regulated voltage control (RVC), if
equipped, are designed to wake-up, perform a task, and go back asleep at regular intervals.
Refer to Body Control System Description and Operation in Computer/Integrating
Systems for the system or modules description and operation.

Remote keyless entry (RKE) will wake up due to an outside input. Refer to Keyless Entry
System Description and Operation in Keyless Entry.

The battery run down time will vary depending on cold cranking amperage (CCA) and
reserve capacity (RC). If the CCA and RC are higher, then the battery run down time would
be longer. If the CCA and RC are lower, then the battery run down time would be shorter.
The graph below indicates roughly how many days a 690 CCA battery with at 110 min. RC
(60.5 AH) starting at 80 percent state of charge will last with a constant current draw until it
reaches 50 percent state of charge. Differences in battery rating and temperature will affect
the results.

Battery Electrical Drain/Parasitic Load Test

IMPORTANT: The battery specification listed below is a generic

specification. Refer to Battery Usage when testing the
battery.

Current Drain

Days

25 mA

30.5

50 mA

16.5

75 mA

100 mA

8.25

250 mA

3.3

500 mA

1.65

750 mA

1 A

0.8

2 A

0.4

CAUTION: Refer to Battery Disconnect Caution in Cautions and Notices.

NOTE:

Do not turn the parasitic draw test switch to the OFF position with
the engine running. Damage will occur to the vehicle's electrical

2006 Hummer H3

2006 ENGINE Engine Electrical - H3

1. Disconnect the battery negative cable from the battery negative terminal.

2. Install the male end of the J 38758 to the battery ground terminal. See Special Tools.

3. Turn the J 38758 knob to the OFF position. See Special Tools.

4. Install the battery negative cable to the female end of the J 38758 . See Special Tools.

5. Connect a 10A fused jumper wire to the test switch tool terminals.

6. Turn the J 38758 knob to the ON position. See Special Tools.

7. Road test the vehicle and activate ALL of the accessories, including the radio and air

conditioning. This may take up to 30 minutes.

8. Park the vehicle. Turn the ignition switch to the OFF position and remove the ignition

switch key.

9. Turn the J 38758 knob to the OFF position. See Special Tools. The current now flows

through the jumper wire.

10. Wait 1 minute. If the fuse blows, install an inductive ammeter and go to step 20.

11. Remove the fused jumper wire.

12. Set a digital multimeter to the 10A scale.

13. Connect the digital multimeter to the test switch tool terminals.

14. Turn the J 38758 knob to the OFF position. See Special Tools. The current flows now

through the digital multimeter.

15. Wait 1 minute. Check and record the current reading.

1. When there is a current reading on 2A or less, turn the J 38758 knob to the ON

position. See Special Tools. The electrical current will now pass through the switch.

2. Then switch the digital multimeter down to the 2A scale for a more accurate reading

system.

NOTE:

The test switch must be in the ON position when removing the fuses
in order to maintain continuity in the electrical system. This avoids
damaging the digital multimeter due to accidental overloading,
such as a door being opened to change a fuse.

IMPORTANT: The switch knob (1) on the J 38758 is marked ON and OFF. See

Special Tools. When the switch knob is in the ON position, the
circuit is closed and electrical current will pass through the
switch. When the switch knob is in the OFF position, the circuit is
open and electrical current will not pass through the switch.

2006 Hummer H3

2006 ENGINE Engine Electrical - H3

when the J 38758 knob is turned OFF. See Special Tools.

16. Turn the J 38758 knob to the OFF position. See Special Tools. Wait 15 minutes for most

vehicles.

17. Check and record the current reading.

18. Note the battery reserve capacity, amp hour rating. Refer to Battery Usage.

1. Divide the reserve capacity by 4, amp hour rating by 2.4.

2. Compare this to the multimeter milliampere reading taken in the previous step. The

parasitic current drain should not exceed this number. Example: If a battery has a
reserve capacity of 100 minutes, (60 A/H) the current drain should not exceed 25 mA.

19. If excessive current drain is not found at this time and there are no other apparent causes,

complete the following:

20. Using the MIN/MAX function of the digital multimeter, monitor the parasitic drain

overnight or during the day. This will determine if something has been activated during that
time frame.

21. When the vehicle has an unacceptable amount of parasitic current drain, remove each fuse

one at a time until the current drain falls to an acceptable level. This will indicate which
circuit is causing the drain. Refer to Power Distribution Schematics in Wiring Systems to
diagnose exactly which part of the suspect circuit is causing the parasitic drain. In some
cases a non-fused circuit or component, such as a relay, is the cause of excessive parasitic
current drain.

22. Repeat the parasitic current drain test procedure after any repair has been completed to

make sure that the parasitic current drain is at an acceptable level.

23. When the cause of the excessive current drain has been located and repaired, remove the J

38758 . See Special Tools.

24. Connect the battery negative cable to the battery negative terminal.

NOTE:

The test switch must be in the ON position when removing the
fuses in order to maintain continuity in the electrical system.
This avoids damaging the digital multimeter due to accidental
overloading, such as a door being opened to change a fuse.

IMPORTANT: Removing fuses, relays, and connectors to determine the

failure area may wake up modules. You must wait for these
modules to go to sleep or use the sleep function on the scan
tool.

2006 Hummer H3

2006 ENGINE Engine Electrical - H3

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