Hummer H2. Manual — part 320

5

z

The headlamp dimmer switch signal

z

The headlamp switch flash to pass (FTP)
signal

Did you find and correct a condition?

Go to Step 18

Go to Step 6

6

Remove the high beam relay.
Do the high beam headlamps remain ON?

Go to Step 12

Go to Step 7

7

Test for a ground signal at the high beam relay
control circuit connector terminal. Refer to
Circuit Testing in Wiring Systems.
Is a ground control signal present?

Go to Step 11

Go to Step 15

8

Remove the low beam relay.
Do the low beam headlamps remain always ON?

Go to Step 13

Go to Step 9

9

Test for a ground signal at the headlamp low
beam relay control circuit connector terminal of
the relay. Refer to Circuit Testing in Wiring
Systems.
Is a ground signal present?

Go to Step 11

Go to Step 16

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 18

Go to Step 17

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 18

Go to Step 14

12

Repair the short to voltage in the right or left
high beam headlamp supply voltage circuit.
Refer to Wiring Repairs in Wiring Systems.
Did you find and correct a condition?

Go to Step 18

-

13

Repair the short to voltage in the right or left
low beam headlamp supply voltage circuit.
Refer to Wiring Repairs in Wiring Systems.
Did you find and correct a condition?

Go to Step 18

-

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 18

-

Replace the high beam headlamp relay. Refer to

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2

HEADLAMPS INOPERATIVE - HIGH BEAMS

Headlamps Inoperative - High Beams

15

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

Go to Step 18

-

16

Replace the low beam 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 18

-

17

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 18

-

18

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 high beam

position.

Do the high beam headlamps operate normally?

Go to Testing for

Intermittent Conditions

and Poor Connections in

Wiring Systems

Go to Step 3

3

Is only one high beam headlamp inoperative?

Go to Step 4

Go to Step 5

4

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

Go to Step 15

Go to Step 8

5

1. Disconnect the headlamp high relay.

2. Connect a test lamp between the control

circuit of the headlamp high relay and the
battery positive voltage circuit of the
headlamp high relay connector.

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2

Does the test lamp illuminate?

Go to Step 13

Go to Step 6

6

1. Connect the headlamp high relay.

2. Test the headlamp dimmer switch signal

and ground circuits for an open or high
resistance. Refer to Circuit Testing and
Wiring Repairs in Wiring Systems.

Did you find and correct a condition?

Go to Step 15

Go to Step 7

7

1. Place the headlamp switch in the ON

position.

2. Connect a fused jumper from ground to the

headlamp dimmer switch signal terminal
of the headlamp dimmer switch connector.

Do the high beam headlamps illuminate?

Go to Step 9

Go to Step 10

8

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 15

Go to Step 11

9

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

Go to Step 15

Go to Step 14

10

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 15

Go to Step 12

11

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

Go to Step 15

-

12 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 15

-

13

Replace the high beam headlamp relay. Refer to
Relay Replacement (Within an Electrical
Center)Relay Replacement (Attached to Wire

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2

HEADLAMPS INOPERATIVE - LOW BEAMS

Headlamps Inoperative - Low Beams

Harness) in Wiring Systems.
Did you complete the replacement?

Go to Step 15

-

14

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 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: 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.

Do the low beam headlamps operate normally?

Go to Testing for

Intermittent Conditions

and Poor Connections in

Wiring Systems

Go to Step 3

3

Is only one low beam headlamp inoperative?

Go to Step 4

Go to Step 5

4

Test the headlamp low beam supply voltage and
ground circuits for high resistance, an open or 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 9

5

1. Disconnect the headlamp low relay.

2. Connect a test lamp between the control

circuit of the headlamp low relay and the
battery positive voltage circuit of the
headlamp low relay connector.

Does the test lamp illuminate?

Go to Step 14

Go to Step 6

6

1. Connect the headlamp low relay.

2. Place the headlamp switch in the HEAD

position.

3. Disconnect the multifunction switch.

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2