GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B2530 00: Front Fog Lamp Control Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Front Fog Lamp Relay Control

2

1

B2530 00

--

  1. Fog Lamps Inoperative
  2. Fog Lamps Always On

Circuit/System Description

The fog lamps are controlled by the body control module (BCM) by inputs from the for lamp switch. When the BCM receives a fog lamps ON command, it grounds the fog lamp relay control circuit in order to energize the FOG LAMP PCB Relay. With the relay energized, battery voltage is applied through the switch side of the relay, the FOG Fuse, and the fog lamps supply voltage circuits to the fog lamps.

Conditions for Running the DTC

The ignition is ON. Park lamps must be ON and the fog lamps must be commanded ON.

Conditions for Setting the DTC

This DTC will set when the BCM detects a short to voltage in the front fog lamp relay control circuit.

Action Taken When the DTC Sets

The BCM will deactivate the fog lamp relay for the remainder of the ignition cycle.

Conditions for Clearing the DTC

    • The conditions for setting the DTC are no longer present.
    • A history DTC clears after 100 malfunction-free ignition cycles.

Reference Information

Schematic Reference

Fog Lights Schematics

Connector End View Reference

Lighting Systems Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

    •  Scan Tool Output Controls
    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Verification

Ignition ON, turn the park lamps ON. Press the front fog lamp switch. The front fog lamps should illuminate.

Circuit/System Testing

  1. Ignition OFF, disconnect the (C2) harness connector at the underhood fuse block.
  2. Connect a test lamp between the control circuit terminal 23 and B+.
  3. Ignition ON, command the fog lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
  4. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM.
    If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuit tests normal, replace the underhood fuse block.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Underhood Electrical Center or Junction Block Replacement
    •  Control Module References for BCM replacement, setup, and programming