Hummer H2. Manual - part 319

5

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

4. With the scan tool, observe the park brake 

switch parameter in the Body Control Module 
(BCM) data list.  

Does the scan tool display RELEASED?

Go to Step 7

Go to Step 6

6

Test the signal circuit of the park brake switch 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 16

Go to Step 10

7

1. Turn OFF the ignition.  

2. Remove the daytime running lamps (DRL) 

relay.  

3. Connect a 3-amp fused jumper wire between 

battery positive voltage and the DRL supply 
voltage circuit of the DRL relay.  

Do the DRL illuminate?

Go to Step 8

Go to Step 11

8

Test the DRL relay control circuit of the DRL relay 
for a ground signal. Refer to Circuit Testing in 
Wiring Systems. 
Is a ground signal present?

Go to Step 14

Go to Step 9

9

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 16

Go to Step 12

10

Inspect for poor connections at the harness connector 
of the park brake 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 16

Go to Step 13

11

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

Go to Step 16

-

12

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 16

-

13

Replace the park brake switch. Refer to Park Brake 
Warning Lamp Switch Replacement in Park Brake.
Did you complete the replacement?

Go to Step 16

-

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2

  

HAZARD LAMPS ALWAYS ON 

Hazard Lamps Always On 

14

Replace the DRL 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 inoperative DRL. Refer to Daytime 
Running Lamp Replacement . 
Did you complete the replacement?

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

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

Turn OFF the hazard flashers. 
Does the system operate normally?

Go to Testing for 

Electrical 

Intermittents in 

Wiring Systems

Go to Step 3

3

1. Turn OFF the ignition.  

2. Disconnect the turn signal/hazard flasher 

module.  

3. Connect a test lamp between the hazard flasher 

signal circuit of the turn signal/hazard flasher 
module connector and battery positive voltage.  

Does the test lamp illuminate?

Go to Step 4

Go to Step 6

4

Test the hazard switch signal circuit of the turn 
signal/hazard flasher module 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 9

Go to Step 5

5

Inspect for poor connections at the harness connector 
of the Multifunction switch. Refer to Circuit Testing 
and Wiring 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 turn signal/hazard flasher module. Refer to 
Testing for Intermittent Conditions and Poor 

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2

  

HAZARD LAMPS INOPERATIVE 

Hazard Lamps Inoperative 

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 multifunction switch. Refer to 
Multifunction, Turn Signal Switch Replacement in 
Steering Wheel and Column. 
Did you complete the replacement?

Go to Step 9

-

8

Replace the turn signal/hazard flasher module. 
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: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

Turn ON the hazard flashers. 
Does the system operate normally?

Go to Testing for 

Electrical 

Intermittents in 

Wiring Systems

Go to Step 3

3

1. Turn ON the ignition with the engine OFF.  

2. Turn ON each turn signal.  

Do the turn signals function properly?

Go to Step 4

Go to Turn Signal 

Lamps and/or 

Indicators 

Inoperative

4

1. Turn OFF the ignition.  

2. Disconnect the turn signal/hazard flasher 

module.  

3. Turn ON the hazard switch.  

4. Connect a test lamp between the hazard flasher 

signal circuit of the turn signal/hazard flasher 
module connector and battery positive voltage.  

Does the test lamp illuminate?

Go to Step 8

Go to Step 5

5

Test the hazard switch signal circuit of the turn 
signal/hazard flasher module for high resistance or an 
open. Refer to Circuit Testing and Wiring Repairs 
in Wiring Systems. 

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2

  

HEADLAMPS ALWAYS ON - LOW OR HIGH BEAM 

Headlamps Always On - Low or High Beam 

Did you find and correct the condition?

Go to Step 11

Go to Step 6

6

Test the ground circuit of the multifunction switch 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 11

Go to Step 7

7

Inspect for poor connections at the harness connector 
of the Multifunction 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 9

8

Inspect for poor connections at the harness connector 
of the turn signal/hazard flasher 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 11

Go to Step 10

9

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

Go to Step 11

-

10

Replace the turn signal/hazard flasher module. 
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: 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

Place the headlamp switch in the OFF position.
Do the high and low beam headlamps operate 
normally?

Go to Testing for 

Intermittent Conditions 

and Poor Connections in 

Wiring Systems

Go to Step 3

3

Are only the high beam headlamps always ON?

Go to Step 4

Go to Step 8

4

Disconnect the headlamp dimmer switch. 
Do the high beam headlamps remain ON?

Go to Step 5

Go to Step 10

Test the following circuits for a short to ground 
as applicable. Refer to Circuit Testing and 
Wiring Repairs in Wiring Systems. 

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2