GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The front fog lamp switch signal circuit is grounded momentarily by pressing the front fog lamp switch. The body control module (BCM) energizes the front fog lamp relay by applying battery positive voltage to the front fog lamps relay control circuit when the front fog lamp relay is energized, battery positive voltage is applied to the front fog lamps supply voltage circuit which illuminates the front fog lamps.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B2530 Front Fog Lamps Control Circuit

Conditions for Running the DTC

The battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

B2530 02

The front fog lamp relay control circuit is shorted to ground.

B2530 05

The front fog lamp relay control circuit is shorted to battery positive voltage or open.

Action Taken When the DTC Sets

B2530 02

The front fog lamps will not operate.

B2530 05

The front fog lamps and the fog lamp indicator will be on at all times or will not operate.

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

Conditions for Clearing the 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

    • The fog lamps will only illuminate under the following conditions:
       - The park lamps or low beam headlamps are ON.
       - The high beam headlamps are OFF.
       - The fog lamp switch is the ON position.
    • If the DTC is a history DTC, the problem may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections .

Step

Action

Yes

No

Schematic Reference: Fog Lights Schematics

Connector End View Reference: Master Electrical Component List

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Turn ON the ignition.
  2. Turn ON the park lamps.
  3. Turn ON the front fog lamps.
  4. Turn OFF the front fog lamps.

Do the front fog lamps turn ON and OFF?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Is DTC B2530 02 present?

Go to Step 4

Go to Step 6

4

  1. Disconnect the underhood electrical center.
  2. Connect a test lamp between battery positive voltage and the front fog lamp relay control circuit.

Does the test lamp illuminate?

Go to Step 5

Go to Step 13

5

Test for a short to ground in the front fog lamp relay control circuit. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 14

Go to Step 8

6

  1. Disconnect the body control module (BCM) Connector C1.
  2. Connect a test lamp between the front fog lamp relay control circuit and ground.

Does the test lamp illuminate?

Go to Step 7

Go to Step 10

7

Test for a short to battery positive voltage in the front fog lamp relay control circuit. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 14

Go to Step 9

8

  1. Remove the front fog lamp relay.
  2. Disconnect the underhood electrical center.
  3. Using a test lamp connected to battery positive voltage probe the front fog lamp relay control circuit at the underhood electrical center.

Does the test lamp illuminate?

Go to Step 12

Go to Step 11

9

  1. Remove the front fog lamp relay.
  2. Disconnect the underhood electrical center connector C2.
  3. Using a test lamp connected to ground, probe the front fog lamp relay control circuit at the underhood electrical center.

Does the test lamp illuminate?

Go to Step 12

Go to Step 11

10

Test for a poor connection or an open in the front fog lamp relay control circuit. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 14

Go to Step 13

11

Replace the front fog lamp relay. Refer to Relay Replacement .

Did you complete the replacement?

Go to Step 14

--

12

Replace the underhood electrical center. Refer to Underhood Electrical Center or Junction Block Replacement .

Did you complete the replacement?

Go to Step 14

--

13

Replace the BCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 14

--

14

  1. Use a 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