GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2007 🢒 Canyon Pickup - 4WD 🢒 Brakes 🢒 Park Brake 🢒 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
    • 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.

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

    2.

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

    3.

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

    4.

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

    5.

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

    6.

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

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

3

  1. Turn OFF the ignition.
  2. Remove the front fog lamp relay. Refer to Relay Replacement .
  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 .

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 .

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