Hummer H2. Manual - part 1916

Certain devices on the vehicle maintain a small continuous current drain on the battery. A battery that is not 
used for an extended period of time will discharge. Eventually permanent damage will result. Discharged 
batteries will also freeze in cold weather. Refer to BATTERY INSPECTION/TEST (NON-HP2) .  

In order to maintain a battery state of charge while storing the vehicle for more than 30 days:  

1.  

Ensure that the green dot is visible in the built-in hydrometer.  

2.  

Disconnect the battery ground to protect the battery from discharge by parasitic current drains.  

When the battery cannot be disconnected:  

1. Maintain a high state of charge.  

2. Establish a regular schedule for recharging the battery every 20-45 days.  

A battery that has remained in a discharged state for a long period of time is difficult to recharge or may be 
permanently damaged.  

JUMP STARTING IN CASE OF EMERGENCY 

NOTE:

If a green dot is not visible in the hydrometer, charge the battery. Refer to 
BATTERY CHARGING . 

CAUTION: Before servicing any electrical component, the ignition key must be 

in the OFF or LOCK position and all electrical loads must be OFF, 
unless instructed otherwise in these procedures. If a tool or 
equipment could easily come in contact with a live exposed electrical 
terminal, also disconnect the negative battery cable. Failure to follow 
these precautions may cause personal injury and/or damage to the 
vehicle or its components. 

CAUTION: Batteries produce explosive gases. Batteries contain corrosive acid. 

Batteries supply levels of electrical current high enough to cause burns. 
Therefore, in order to reduce the risk of personal injury while working near 
a battery, observe the following guidelines: 

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Always shield your eyes.  

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Avoid leaning over the battery whenever possible.  

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Do not expose the battery to open flames or sparks.  

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Do not allow battery acid to contact the eyes or the skin.  

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Flush any contacted areas with water immediately and thoroughly.  

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Get medical help.  

 

2004 Hummer H2 

2004 STARTING & CHARGING SYSTEMS Starters - H2

  

This vehicle has a 12-volt positive, negative ground electrical system. Do not try to jump start a vehicle, if you 
are unsure of the other vehicle's positive voltage or ground position. The booster battery and the discharged 
battery should be treated carefully when using jumper cables.  

1. Position the vehicle with the booster battery so that the jumper cables will comfortably reach the battery 

of the other vehicle. 

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Do not let the 2 vehicles touch.  

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Make sure that the jumper cables do not have loose clamps or missing insulation.  

2. Perform the following steps on both vehicles: 

A. Place the automatic transmission in PARK.  

B. Block the wheels.  

C. Set the parking brake.  

D. Turn off all electrical loads that are not needed. Leave the hazard flashers ON.  

E. Turn OFF the ignition switch.  

3.  

Attach the end of one jumper cable to the positive terminal of the discharged battery.  

4. Attach the other end of the first cable to the positive terminal of the booster battery.  

5. Attach one end of the remaining jumper cable to the negative terminal of the booster battery.  

6.  

Make the final connection of the negative jumper cable to the block or suitable bracket connected directly 
to the block, away from the battery.  

7. Start the engine of the vehicle that is providing the jump start and turn off all electrical accessories. Raise 

the engine RPM to approximately 1,500 RPM.  

8. Crank the engine of the vehicle with the weak battery. If the engine does not crank or cranks too slowly, 

perform the following steps: 

A. Turn the ignition OFF.  

B. Allow the booster vehicle engine to run at approximately 1,500 RPM for 5 minutes.  

C. Attempt to start the engine of the vehicle with the discharged battery.  

NOTE:

This vehicle has a 12 volt, negative ground electrical system. Make sure the 
vehicle or equipment being used to jump start the engine is also 12 volt, 
negative ground. Use of any other type of system will damage the vehicle's 
electrical components. 

NOTE:

Some vehicles have a battery remote positive stud. ALWAYS use the 
battery remote positive stud in order to give or to receive a jump start. 
Consult the vehicle's owner's manual for proper connections. 

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. 

 

2004 Hummer H2 

2004 STARTING & CHARGING SYSTEMS Starters - H2

  

9. Reverse the steps exactly when removing the jumper cables. The negative battery cable must first be 

disconnected from the engine that was jump started.  

REMOVAL & INSTALLATION 

BATTERY NEGATIVE CABLE DISCONNECT/CONNECT PROCEDURE (SINGLE BATTERY) 

Removal Procedure 

1. Turn off all the lamps and accessories.  

2. Turn the ignition OFF.  

3. Remove the battery ground negative cable and bolt from the battery.  

Installation Procedure 

Install the battery ground negative cable and bolt to the battery. Tighten the battery terminal bolt to 17 N.m (13 
lb ft).  

BATTERY NEGATIVE CABLE REPLACEMENT 

Removal Procedure 

1. Disconnect the battery negative cable from the battery. See BATTERY NEGATIVE CABLE 

DISCONNECT/CONNECT PROCEDURE (SINGLE BATTERY) .  

2. Raise and suitably support the vehicle with safety stands.  

3. Remove the engine protection shield.  

4. Remove the forward lamp wiring harness ground/negative cable bolt.  

5. Remove the engine wiring harness ground/negative cable bolt.  

6. Remove the negative battery cable. 

NOTE:

Clean any existing corrosion from the battery terminal bolt flange and the 
battery cable end. 

CAUTION: Before servicing any electrical component, the ignition key must be in the 

OFF or LOCK position and all electrical loads must be OFF, unless 
instructed otherwise in these procedures. If a tool or equipment could 
easily come in contact with a live exposed electrical terminal, also 
disconnect the negative battery cable. Failure to follow these precautions 
may cause personal injury and/or damage to the vehicle or its 
components. 

 

2004 Hummer H2 

2004 STARTING & CHARGING SYSTEMS Starters - H2

  

Fig. 6: Locating Negative Battery Cable-To-Engine Connection 
Courtesy of GENERAL MOTORS CORP. 

Installation Procedure 

1. Install the negative battery cable.  

2. Position the negative cable and forward lamp wiring harness ring terminals to the frame. Insert the anti-

rotation tab on the forward lamp wiring harness into the hole in the frame.  

3. Install the forward lamp wiring harness ground/negative cable bolt. Tighten the forward lamp wiring 

harness ground/negative cable bolt to 9 N.m (80 lb in).  

4. Position the negative cable and engine wiring harness ring terminals to the engine block. Position the 

anti-rotation tab on the negative cable in the correct location. 

 

2004 Hummer H2 

2004 STARTING & CHARGING SYSTEMS Starters - H2