Hummer H2. Manual - part 325

PARK, LICENSE, AND TAIL LAMPS INOPERATIVE 

Park, License, and Tail Lamps Inoperative 

12

Replace the BCM. Refer to Body Control 
Module Replacement in Body Control 
System.Did you complete the replacement?

Go to Step 13

-

13

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:Exterior Lights 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

Verify that the park, license and tail lamps are 
inoperative. 
Do the park, license and tail lamps operate 
normally?

Go to Testing for 

Intermittent Conditions 

and Poor Connections in 

Wiring Systems

Go to Step 3

3

Are all park, license, and tail lamps inoperative?

Go to Step 6

Go to Step 4

4

Test the supply circuit of the inoperative lamp 
for high resistance or an open. Refer to Circuit 
Testing and Wiring Repairs in Wiring 
Systems. 
Did you find and correct the condition?

Go to Step 15

Go to Step 5

5

Test the ground circuit of the inoperative lamp 
for high resistance or an open. Refer to Circuit 
Testing and Wiring Repairs in Wiring 
Systems. 
Did you find and correct the condition?

Go to Step 15

Go to Step 11

6

1. Remove the park lamp relay.  

2. Ensure that the headlamp switch is in the 

ON position.  

3. Test for a ground signal at the park lamp 

relay control circuit terminal in the 
underhood fuse block. Refer to Circuit 
Testing in Wiring Systems.  

Was a ground signal present?

Go to Step 12

Go to Step 7

7

Use the scan tool to check the body control 
module (BCM) parklamp switch input data. 
Does the scan tool indicate a park lamps ON 
request signal?

Go to Step 10

Go to Step 8

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2

  

READING LAMP(S) INOPERATIVE 

Reading Lamp(s) Inoperative 

8

Test for an open or high resistance in the park 
lamp switch signal circuit. Refer to Circuit 
Testing and Wiring Repairs in Wiring 
Systems. 
Did you find and correct the condition?

Go to Step 15

Go to Step 9

9

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

Go to Step 15

Go to Step 13

10

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

Go to Step 15

Go to Step 14

11

Replace the inoperative bulb. 
Did you complete the replacement?

Go to Step 15

-

12

Replace the park lamp relay. Refer to Relay 
Replacement (Within an Electrical Center)
Relay Replacement (Attached to Wire 
Harness) in Wiring Systems. 
Did you complete the repair?

Go to Step 15

-

13

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

Go to Step 15

-

14

Replace the 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 15

-

15

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: Interior Lights SchematicsBody Control System 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 Diagnostic System 
Check?

Go to Step 2

Go to Diagnostic 

System Check - 

Lighting Systems

Turn ON the reading lamps. 

Go to Testing for 

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2

  

STOP LAMPS ALWAYS ON 

Stop Lamps Always On 

2

Does the system operate normally?

Electrical Intermittents 

in Wiring Systems

Go to Step 3

3

Are all of the reading, visor and I/P compartment 
lamps inoperative?

Go to Step 4

Go to Step 6

4

Is the TBC 2C Fuse in the I/P fuse block open?

Go to Step 5

Go to Step 6

5

Test the battery positive voltage circuit of the BCM 
for a short to ground. Refer to Circuit Testing and 
Wiring Repairs in Wiring Systems. 
Did you find and correct the condition?

Go to Step 12

Go to Step 9

6

Test the inadvertent power supply voltage circuit of 
the reading lamp for a short to ground, high 
resistance or an open. Refer to Circuit Testing and 
Wiring Repairs in Wiring Systems. 
Did you find and correct the condition?

Go to Step 12

Go to Step 7

7

Test the ground circuit of the reading lamp for high 
resistance or an open. 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

8

Inspect the inoperative bulb for an open filament. 
Is the bulb OK.

Go to Step 7

Go to Step 6

9

Repair the inadvertent power supply voltage circuit 
for a short to ground. Refer to Wiring Repairs in 
Wiring Systems. 
Did you complete the repair?

Go to Step 12

-

10

Replace the inoperative bulb. Refer to Reading 
Lamp and Bulb Replace - Overhead Console . 
Did you complete the replacement?

Go to Step 12

-

11

Replace the dome lamp. Refer to Dome Lamp 
Replacement in Interior Trim. 
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: Exterior Lights 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 Diagnostic System 
Check?

Go to Step 2

Go to Diagnostic 

System Check - 

Lighting Systems

Depress the brake pedal. 
Does the system operate normally?

Go to Testing for 

Electrical 

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2

  

STOP LAMPS INOPERATIVE 

Stop Lamps Inoperative 

2

Intermittents in Wiring 

Systems

Go to Step 3

3

Disconnect the stop lamp switch. 
Do the brake lamps go out?

Go to Step 6

Go to Step 4

4

Remove the CHMSL fuse. 
Do the brake lamps go out?

Go to Step 7

Go to Step 5

5

Remove the STOP fuse. 
Do the brake lamps go out?

Go to Step 8

Go to Step 9

6

Inspect for poor connections at the harness 
connector of the switch. 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 11

Go to Step 10

7

Repair the short to voltage in the CHMSL supply 
voltage circuit. Refer to Wiring Repairs in Wiring 
Systems. 
Did you complete the repair?

Go to Step 11

-

8

Repair the short to voltage in the stop lamp switch 
signal circuit. Refer to Wiring Repairs in Wiring 
Systems. 
Did you complete the repair?

Go to Step 11

-

9

Repair the short to voltage in the stop lamp supply 
voltage circuit. Refer to Wiring Repairs in Wiring 
Systems. 
Did you complete the repair?

Go to Step 11

-

10

Replace the stop lamp switch. Refer to Stop Lamp 
Switch Replacement . 
Did you complete the replacement?

Go to Step 11

-

11

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: Exterior Lights 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 Diagnostic System 
Check?

Go to Step 2

Go to Diagnostic 

System Check - 

Lighting Systems

2

Observe the stop lamps while pressing the brake 
pedal. 
Does the system operate normally?

Go to Testing for 

Electrical 

Intermittents in 

Wiring Systems

Go to Step 3

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2