Hummer H3. Manual — part 1404

DTC B2557 Passenger Compartment Lamp Control Circuit Low

DTC B2558 Passenger Compartment Lamp Control Circuit High

Conditions for Running the DTC

The battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

When the BCM receives a courtesy lamp illumination request signal and the inadvertent
power supply voltage circuit is shorted to ground

When the BCM is not receiving a courtesy lamp illumination request signal and the
inadvertent power supply voltage circuit is shorted to voltage

There is a loss of the underhood fuse block truck body controller (TBC) battery supply
voltage to the BCM for more than 1 second.

Action Taken When the DTC Sets

The courtesy/dome lamps will not operate or are always ON.

Conditions for Clearing the MIL/DTC

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

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

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

Diagnostic Aids

Perform a visual inspection for loose or poor connections at all related components. Refer to
Testing for Intermittent Conditions and Poor Connections .

Test Description

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

2: This step determines if the problem exists in the wiring.

3: This step determines if a condition exist in the TBC battery voltage supply circuit.

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

DTC B2557 or B2558

Step

Action

Yes

No

2007 Hummer H3

2007 ACCESSORIES & EQUIPMENT Lighting - H3

DTC B2575

Circuit Description

Schematic Reference: Interior Lights Schematics
Connector End View Reference: Lighting Systems Connector End Views or Data
Communication Connector End Views

1

Did you perform the Diagnostic System
Check - Vehicle?

Go to Step 2

Go to
Diagnostic
System Check -
Vehicle

2

Test the inadvertent power supply voltage
circuit for a short to voltage or short to
ground. Refer to Circuit Testing and
Wiring Repairs .
Did you find and correct the condition?

Go to Step 6

Go to Step 3

3

Test the truck body controller (TBC)
battery positive supply voltage circuit for a
short to ground, open or high resistance.
Refer to Circuit Testing .
Did you find and correct the condition?

Go to Step 6

Go to Step 4

4

Inspect for poor connections at the harness
connectors of the body control module
(BCM). Refer to Testing for
Intermittent Conditions and Poor
Connections and Connector Repairs .
Did you find and correct the condition?

Go to Step 6

Go to Step 5

5

Replace the BCM. Refer to Control
Module References for replacement,
setup and programming.
Did you complete the replacement?

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

2007 Hummer H3

2007 ACCESSORIES & EQUIPMENT Lighting - H3

When the body control module (BCM) senses a request for headlamp or daytime running lamp
(DRL) illumination, the BCM sends a ground signal to the headlamp relay through the low beam
headlamp relay control circuit. The headlamp relay will illuminate the low beam headlamps.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B2575 Headlamp Control Circuit

Conditions for Running the DTC

The battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

When the BCM receives a command to illuminate the headlamps and the headlamp low
beam relay control circuit is open or shorted to voltage

When the BCM does not receive a command to illuminate the headlamps and the headlamp
low beam relay control circuit is shorted to ground

Action Taken When the DTC Sets

The headlamps will not operate or will remain always ON.

Conditions for Clearing the MIL/DTC

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

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

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

Test Description

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

3: This step tests for voltage at the voltage supply side of the headlamp relay.

4: This step verifies that the BCM is providing ground to the headlamp relay.

5: This step tests if ground is constantly being applied to the headlamp relay.

6: This step tests if there is opposing voltage present or an open low beam headlamp relay
control circuit.

12: After replacement of the BCM, you must calibrate the new module for proper

2007 Hummer H3

2007 ACCESSORIES & EQUIPMENT Lighting - H3

operation.

DTC B2575

Step

Action

Yes

No

Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics
Connector End View Reference: Lighting Systems Connector End Views or Data
Communication Connector End Views

1

Did you perform the Diagnostic System
Check - Vehicle?

Go to Step 2

Go to

Diagnostic

System Check -

Vehicle

2

1. Install a scan tool.

2. Turn ON the ignition, with the

engine OFF.

3. With a scan tool, command the

headlamps ON and OFF.

Does the headlamp relay turn ON and
OFF with each command?

Go to Testing

for Intermittent

Conditions and

Poor

Connections

Go to Step 3

3

1. Turn OFF the ignition.

2. Disconnect the headlamp relay.

3. Turn ON the ignition, with the

engine OFF.

4. Probe the battery positive voltage

circuit of the headlamp relay with a
test lamp that is connected to a good
ground.

Does the test lamp illuminate?

Go to Step 4

Go to Step 10

4

1. Connect a test lamp between the

control circuit of the headlamp relay
and the battery positive voltage
circuit of the headlamp relay.

2. With a scan tool, command the

headlamps ON and OFF.

Does the test lamp turn ON and OFF with

2007 Hummer H3

2007 ACCESSORIES & EQUIPMENT Lighting - H3