Hummer H3. Manual — part 1403

DTC B2532 OR B2533

Circuit Description

When the body control module (BCM) senses that the front fog lamp switch signal circuit is
grounded momentarily by pressing the front fog lamp switch, the BCM energizes the front fog
lamp relay by grounding the front fog lamp relay control circuit. The front fog lamp indicator is
also illuminated utilizing the same fog lamp relay control circuit.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

DTC B2532 Front Fog Lamps Control Circuit Low

DTC B2533 Front Fog Lamps 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 front fog lamp switch OFF command and the front fog lamp relay
control circuit is shorted to ground

When the BCM receives a front fog lamp switch ON command and the front fog lamp relay
control circuit is shorted to voltage or open

Action Taken When the DTC Sets

The front fog lamps will not operate or will remain always ON.

Conditions for Clearing the MIL/DTC

14

and programming.
Did you complete the replacement?

Go to Step 15

-

15

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

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.

2: Listen for an audible click when the front fog lamp relay operates. Command both the
ON and OFF states. Repeat the commands as necessary.

3: This step tests for ground at the coil side of the front fog lamp relay.

4: This step verifies that the BCM is providing battery positive voltage to the front fog lamp
relay.

5: This step tests if battery positive voltage is constantly being applied to the front fog lamp
relay.

6: This step tests if a condition exists in the front fog lamp relay control circuit.

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

DTC B2532 or B2533

Step

Action

Yes

No

Schematic Reference: Fog 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

1. Install a scan tool.

2. Turn ON the ignition, with the engine

OFF.

3. With a scan tool, command the front

fog lamp relay ON and OFF.

Does the front fog lamp relay turn ON and
OFF with each command?

Go to Testing

for Intermittent

Conditions and

Poor

Connections

Go to Step 3

1. Turn OFF the ignition.

2007 Hummer H3

2007 ACCESSORIES & EQUIPMENT Lighting - H3

3

2. Remove the front fog lamp relay.

Refer to Relay Replacement
(Attached to Wire Harness) or
Relay Replacement (Within an
Electrical Center) .

3. Turn ON the ignition, with the engine

OFF.

4. Connect a test lamp between the

ground circuit of the front fog lamp
relay and the battery positive voltage
circuit of the front fog lamp relay.

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 front fog lamp
relay and the ground circuit of the
front fog lamp relay.

2. With a scan tool, command the front

fog lamp relay ON and OFF.

Does the test lamp turn ON and OFF with
each command?

Go to Step 8

Go to Step 5

5

Does the test lamp remain illuminated with
each command?

Go to Step 7

Go to Step 6

6

Test for a short to ground, an open or high
resistance in the fog lamp relay control
circuit and fog lamp switch indicator control
circuit. Refer to Circuit Testing and
Wiring Repairs .
Did you find and correct the condition?

Go to Step 13

Go to Step 9

7

Test for a short to voltage in the fog lamp
relay control circuit and fog lamp switch
indicator control circuit. Refer to Circuit
Testing and Wiring Repairs .
Did you find and correct the condition?

Go to Step 13

Go to Step 9

8

Inspect for poor connections at the front fog
lamp relay. Refer to Circuit Testing and
Wiring Repairs .

2007 Hummer H3

2007 ACCESSORIES & EQUIPMENT Lighting - H3

DTC B2557 OR B2558

Circuit Description

The body control module (BCM) receives a ground signal from the door jamb or dome lamp
switches requesting courtesy/dome lamp illumination. When this occurs, the BCM directly sends a
voltage through the inadvertent power supply voltage circuit illuminating the courtesy/dome
lamps.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

Did you find and correct the condition?

Go to Step 13

Go to Step 11

9

Inspect for poor connections at the harness
connector of the body control module
(BCM). Refer to Circuit Testing and
Wiring Repairs .
Did you find and correct the condition?

Go to Step 13

Go to Step 12

10

Repair the open or high resistance in the
ground circuit of the front fog lamp relay.
Refer to Wiring Repairs .
Did you complete the repair?

Go to Step 13

-

11

Replace the front fog lamp relay. Refer to
Relay Replacement (Attached to Wire
Harness) or Relay Replacement (Within
an Electrical Center) .
Did you complete the replacement?

Go to Step 13

-

12

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

Go to Step 13

-

13

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