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