Hummer H2. Manual — part 308

Front Wipers Active

The scan tool displays the position of the front wiper switch. The scan tool displays Yes when the front
wiper switch is in the ON position. The BCM uses this data in controlling the operation of the automatic
lamp control (ALC).

Headlamp Switch

The scan tool displays the position of the headlamp switch. The scan tool displays Active when the
headlamp switch is in the ON position. The BCM uses this data in controlling the operation of the
headlamps.

High Beam Switch

The scan tool displays the position of the high beam switch. The scan tool displays On when the switch is
used to activate the high beams.

Ignition 0

The scan tool displays the position of the ignition switch. The scan tool displays On when the ignition
switch is in the RUN or CRANK position.

Ignition 1

The scan tool displays the position of the ignition switch. The scan tool displays On when the ignition
switch is in the RUN or CRANK position.

Ignition Accessory

The scan tool displays the position of the ignition switch. The scan tool displays Active when the ignition
switch is in the ACCESSORY position only.

Inadvertent Power Relay

The scan tool displays the state of the inadvertent power battery rundown protection feature of the BCM.
The scan tool displays Off when all inadvertent power circuits are functioning normally.

Interior Lamp Defeat Switch

The scan tool displays the position of the courtesy/dome lamp override switch. The scan tool displays On
when the switch is activated requesting the BCM to override the normal interior lamp activation inputs
and deactivate the interior lighting.

Left Rear/Rear Cargo Door

The scan tool displays Off when the left rear door is fully closed or On when the door is ajar or open.

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2

Park Lamp Switch

The scan tool displays the position of the park lamp switch. The scan tool displays Active when the park
lamp switch is in the ON position. The BCM uses this data in controlling the operation of the park lamps.

Right Rear Door Ajar Switch

The scan tool displays Off when the right rear door is fully closed or On when the right rear door is open
or ajar.

Outputs

Backup Lamps

The scan tool displays the commanded state of the relay. The scan tool displays On when the BCM
allows the relay to go to ground to activate the lamps.

Daytime Running Lamps

The scan tool displays the commanded state of the DRL relay. The scan tool displays Active when the
BCM allows the DRL beam relay to go to ground to activate the DRL.

Headlamps On Indicator

The scan tool displays the commanded state of the headlamps. The scan tool displays On when the BCM
allows the headlamps On.

High Beam Relay

The scan tool displays the commanded state of the high beam relay. The scan tool displays On when the
BCM allows the high beam relay to go to ground to activate the high beam headlamps.

Park Lamp Relay

The scan tool displays the commanded state of the relay. The scan tool displays On when the BCM
allows the relay to go to ground to activate the lamps.

DIAGNOSTIC TROUBLE CODE (DTC) LIST

Diagnostic Trouble Code (DTC) List

DTC

Diagnostic Procedure

Module

B1480

DTC B1480

BCM

B2550

DTC B2550

BCM

B2575

DTC B2575

BCM

B2580

DTC B2580

BCM

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2

DTC B1480

Circuit Description

The body control module (BCM) supplies battery positive voltage to the individually controlled lamps. In the
event that any of these lamps were to remain illuminated for more than 20 minutes with the ignition switch in
the OFF position, the BCM will deactivate the inadvertent power supply voltage circuit to prevent a total
battery discharge condition.

Voltage for the inadvertent power supply voltage circuit is from the TBC 2C fuse in the instrument panel (I/P)
fuse block directly through the BCM to this circuit.

Conditions for Running the DTC

The battery voltage must be between 9.0-16.0 volts.

Conditions for Setting the DTC

z

The inadvertent power supply voltage circuit is shorted to ground for more than 1 second.

z

There is a loss of the instrument panel fuse block TBC 2C battery supply voltage to the BCM for 1
second while one or more of the lamps in the inadvertent power circuit has been activated.

Action Taken When the DTC Sets

The lamps on the inadvertent power supply voltage circuit will not operate.

Conditions for Clearing the MIL/DTC

z

This DTC will clear on current status after the condition for setting the fault is corrected.

z

A history DTC will clear after 100 consecutive ignition cycles without a fault present.

z

History and current DTCs can be cleared using a scan tool.

Diagnostic Aids

z

Perform a visual inspection for loose or poor connections at all related components. Refer to Testing for

B2585

DTC B2585

BCM

B2600

DTC B2600

BCM

B2610

DTC B2610

BCM

B2615

DTC B2615

BCM

B2620

DTC B2620

BCM

B2625

DTC B2625

BCM

B2645

DTC B2645

BCM

B3801

DTC B3801

BCM

B3802

DTC B3802

BCM

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2

Intermittent Conditions and Poor Connections in Wiring Systems.

z

A short to ground in the inadvertent power supply voltage circuit or the battery positive voltage circuit
will cause the TBC 2C fuse to open.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

3: This step test determines if the problem exists in the wiring or the BCM.

5: After replacement of the BCM you must calibrate the new module for proper operation.

DTC B1480

DTC B2550

Circuit Description

Step

Action

Yes

No

Schematic Reference: Interior 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 System Diagnostic System Check?

Go to

Step 2

Go to Diagnostic

System Check -

Lighting Systems

2

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

Go to

Step 3

Go to Step 4

3

Test the inadvertent power supply voltage circuit, and the TBC 2C
battery supply voltage to 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 6

Go to Step 4

4

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 6

Go to Step 5

5

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 6

-

6

1. Use the scan tool in order to clear the DTCs.

2. Operate the vehicle within the Conditions for Running the

DTC as specified in the supporting text.

Does the DTC reset?

Go to

Step 2

System OK

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Lighting Systems - Hummer H2