Hummer H2. Manual - part 321

 

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Hummer H2. Manual - part 321

 

 

Do the low beam headlamps illuminate?

Go to Step 7

Go to Step 10

7

Test the headlamp dimmer switch signal circuit for 
a short to ground. Refer to Circuit Testing and 
Wiring Repairs in Wiring Systems. 
Did you find and correct a condition?

Go to Step 16

Go to Step 8

8

Test the headlamp switch flash to pass signal 
circuit for a short to ground. Refer to Circuit 
Testing and Wiring Repairs in Wiring Systems. 
Did you find and correct a condition?

Go to Step 16

Go to Step 11

9

Inspect for poor connections at the harness 
connector of the inoperative bulb. Refer to Circuit 
Testing and Wiring Repairs in Wiring Systems. 
Did you find and correct the condition?

Go to Step 16

Go to Step 12

10

Inspect for poor connections at the harness 
connector of the headlamp dimmer switch. Refer 
to Circuit Testing and Wiring Repairs in Wiring 
Systems. 
Did you find and correct the condition?

Go to Step 16

Go to Step 15

11

Inspect for poor connections at the harness 
connector of the Body Control Module (BCM). 
Refer to Circuit Testing and Wiring Repairs in 
Wiring Systems. 
Did you find and correct the condition?

Go to Step 16

Go to Step 13

12

Replace the inoperative bulb. Refer to Headlamp 
Bulb Replacement or Headlamp Replacement .
Did you complete the replacement?

Go to Step 16

-

13 Replace the body control module (BCM). Refer to 

Body Control Module Replacement in Body 
Control System.Did you complete the 
replacement?

IMPORTANT:

Perform the setup procedure for the BCM.

Go to Step 16

-

14

Replace the low beam headlamp relay. Refer to 
Relay Replacement (Within an Electrical 
Center)Relay Replacement (Attached to Wire 
Harness) in Wiring Systems. 
Did you complete the replacement?

Go to Step 16

-

15

Replace the headlamp dimmer switch. Refer to 
Multifunction, Turn Signal Switch 
Replacement in Steering Wheel and Column. 
Did you complete the repair?

Go to Step 16

-

16

Operate the system in order to verify the repair. 
Did you correct the condition?

System OK

Go to Step 3

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2

  

HEADLAMPS INOPERATIVE - LOW AND HIGH BEAMS (ALL)

Headlamps Inoperative - Low and High Beams (All) 

Step

Action

Yes

No

Schematic Reference:Headlights Schematics 
Connector End View Reference:Lighting Systems Connector End Views or Body Control System 
Connector End Views in Body Control System

1

Did you perform the Lighting System 
Diagnostic System Check?

Go to Step 2

Go to Diagnostic System 

Check - Lighting 

Systems

2

1. Place the headlamp switch in the ON 

position.  

2. Change the dimmer switch position 

from the high to low beam positions 
several times.  

Does the headlamp system operate 
normally?

Go to Testing for 

Intermittent Conditions 

and Poor Connections in 

Wiring Systems

Go to Step 3

3

Are both high and low beam headlamps 
inoperative?

Go to Step 4

Refer to Headlamps 

Inoperative - Low 

Beams or Headlamps 

Inoperative - High 

Beams

4

With a scan tool, observe the Headlamp 
Switch parameter. 
Does the scan tool indicate ACTIVE?

Go to Step 7

Go to Step 5

5

Connect a test lamp, between the ground 
circuit of the headlamp switch connector and 
battery positive voltage. 
Does the test lamp illuminate?

Go to Step 6

Go to Step 9

6

Test headlamps switch headlamps on signal 
circuit of the headlamp switch. Refer to 
Circuit Testing and Wiring Repairs in 
Wiring Systems. 
Did you find and correct the condition?

Go to Step 12

Go to Step 8

7

Inspect for poor connections to the BCM. 
Refer to Testing for Intermittent 
Conditions and Poor Connections and 
Connector Repairs in Wiring Systems. 
Did you find and correct the condition?

Go to Step 12

Go to Step 10

8

Inspect for poor connections to the 
headlamp switch. Refer to Testing for 
Intermittent Conditions and Poor 
Connections and Connector Repairs in 
Wiring Systems. 

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2

  

HEADLAMPS INOPERATIVE - LOW AND HIGH BEAMS (WITH FRONT WIPERS ON) 

Headlamps Inoperative - Low and High Beams (With Front Wipers On) 

Did you find and correct the condition?

Go to Step 12

Go to Step 11

9

Repair the ground circuit of the headlamp 
switch. Refer to Wiring Repairs in Wiring 
Systems. 
Did you complete the repair?

Go to Step 12

-

10

Replace the body control module. Refer to 
Body Control Module ReplacementDid 
you complete the replacement?

IMPORTANT:

Perform the setup procedure for the body 
control module.

Go to Step 12

-

11

Replace the headlamp switch. Refer to 
Headlamp Switch Replacement 
Did you complete the replacement?

Go to Step 12

-

12

Operate the system in order to verify the 
repair. 
Did you correct the condition?

System OK

Go to Step 3

Step

Action

Yes

No

Schematic Reference:Headlights Schematics 
Connector End View Reference:Lighting Systems Connector End Views or Body Control System 
Connector End Views in Body Control System

1

Did you perform the Lighting Systems Diagnostic 
System Check?

Go to Step 2

Go to Diagnostic 

System Check - 

Lighting Systems

2

1. Turn ON the ignition, with the engine OFF.  

2. Place the headlamp switch in the AUTO 

position.  

3. Place the front windshield wipers in the low 

position.  

Do the headlamps operate as expected?

Go to Testing for 

Intermittent Conditions 

and Poor Connections in 

Wiring Systems

Go to Step 3

3

1. Install a scan tool.  

2. With a scan tool, observe the Front Wiper 

Switch parameter in the BCM data list.  

Does the scan tool indicate that the Front Wiper 
Switch parameter states Active?

Go to Step 5

Go to Step 4

Test the windshield wiper switch signal 2 circuit 

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2

  

HEADLAMPS INOPERATIVE - FLASH TO PASS 

Headlamps Inoperative - Flash to Pass 

4

for high resistance, an open or a short to ground or 
a short to voltage. Refer to Circuit Testing and 
Wiring Repairs in Wiring Systems. 
Did you find and correct the condition?

Go to Step 9

Go to Step 6

5

Inspect for poor connections at the harness 
connector of the BCM. Refer to Testing for 
Intermittent Conditions and Poor Connections 
and Connector Repairs in Wiring Systems. 
Did you find and correct the condition?

Go to Step 9

Go to Step 7

6

Inspect for poor connections at the harness 
connector of the windshield wiper module. Refer to 
Testing for Intermittent Conditions and Poor 
Connections and Connector Repairs in Wiring 
Systems. 
Did you find and correct the condition?

Go to Step 9

Go to Step 8

7

Replace the body control module (BCM). Refer to 
Body Control Module Replacement in Body 
Control System.Did you complete the replacement?

IMPORTANT:

Perform the setup procedure for the BCM.

Go to Step 9

-

8

Replace the windshield wiper module. Refer to 
Wiper Motor Replacement in Wipers/Washer 
Systems. 
Did you complete the replacement?

Go to Step 9

-

9

Operate the system in order to verify the repair. 
Did you correct the condition?

System OK

Go to Step 3

Step

Action

Yes

No

Schematic Reference:Headlights/Daytime Running Lights (DRL) Schematics 
Connector End View Reference:Lighting Systems Connector End Views or Body Control System 
Connector End Views in Body Control System

1

Did you perform the Lighting Systems Diagnostic 
System Check?

Go to Step 2

Go to Diagnostic 

System Check - 

Lighting Systems

2

1. Place the headlamp switch in the ON 

position.  

2. Place the dimmer switch in the low beam 

position.  

3. Turn ON the flash to pass switch.  

Go to Testing for 

Intermittent Conditions 

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2

  

 

 

 

 

 

 

 

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