Hummer H2. Manual - part 1123

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 (NON HP2) 

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. 

z

Do not let the 2 vehicles touch.  

z

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

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

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: 

z

Always shield your eyes.  

z

Avoid leaning over the battery whenever possible.  

z

Do not expose the battery to open flames or sparks.  

z

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

{

Flush any contacted areas with water immediately and 
thoroughly.  

{

Get medical help.  

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.

 

2004 Hummer H2 

2004 ELECTRICAL Engine Electrical - Hummer H2

  

2. Perform the following steps on both vehicles: 

1. Place the automatic transmission in PARK.  

2. Block the wheels.  

3. Set the parking brake.  

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

5. Turn OFF the ignition switch.  

 

2004 Hummer H2 

2004 ELECTRICAL Engine Electrical - Hummer H2

  

Fig. 6: Connecting Battery Terminal Jumpers 
Courtesy of GENERAL MOTORS CORP. 

IMPORTANT: 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.

 

2004 Hummer H2 

2004 ELECTRICAL Engine Electrical - Hummer H2

  

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: 

1. Turn the ignition OFF.  

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

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

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.  

CHARGING SYSTEM TEST (CS/AD/SI GENERATORS) 

Charging System Test (CS/AD/SI Generators) 

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.

Step

Action

Value

(s)

Yes

No

1

Did you perform the Engine Electrical Diagnostic System 
Check?

-

Go to 

Step 2

Go to Diagnostic 

System Check - 

Engine Electrical

2

Start the engine. Observe the charge indicator on the 
instrument cluster (IPC). 
Does the charge indicator illuminate or message center (DIC) 
display a charging system message?

-

Go to 

Step 3

Go to Symptoms - 

Engine Electrical

3

1. Turn OFF the ignition.  

2. Connect the red lead of the J 41450-B Universal CS 

Generator Test Harness to the generator output 
terminal.  

3. Connect the black lead of the J 41450-B to the metal 

IMPORTANT:

The green POWER lamp of the tester should remain 
illuminated while the tester is being used.

-

 

2004 Hummer H2 

2004 ELECTRICAL Engine Electrical - Hummer H2