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 Circuit

1

2

B2530 00

--

  1. Fog Lamps Always On
  2. Fog Lamps Inoperative

Circuit/System Description

Voltage is applied at all times to the fog lamp relay. When the fog lamp switch is placed in the ON position, a ground signal is applied to the body control module (BCM) through the fog lamp switch signal circuit. The BCM then applies a ground to the front fog lamp control circuit. This engages the fog lamp relay and applies voltage through the FOG LAMP fuse to the front 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

The BCM detects a short to voltage on the front fog lamp control circuit.

Action Taken When the DTC Sets

The front fog lamps do not illuminate.

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.
    • The BCM receives the clear code command from the scan tool.

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, activate the Fog Lamps output control on the scan tool. The Front Fog Lamp Relay Command parameter in the data list should display On and the front fog lamps should illuminate.

Circuit/System Testing

  1. Ignition OFF, remove the fog lamp relay in the underhood fuse block.
  2. Ignition ON, test for voltage at the relay control circuit terminal of the underhood fuse block.
  3. If voltage is present, test the control circuit for a short to voltage. If all circuits/connections test normal, replace the fog lamp relay.
    If voltage is not present, replace the BCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Relay Replacement
    •  Control Module References for BCM replacement, setup, and programming