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 Descriptors

DTC B2532 00: Front Fog Lamps Control Circuit Low

DTC B2533 00: Front Fog Lamps Control Circuit High

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Front Fog Lamp Relay Control

B2532 00

1

B2533 00

--

Front Fog Lamp Switch Control

1

1

1

--

Front Fog Lamp Indicator Control

1

1

1

--

Front Fog Lamp Control

1

1

1

--

Front Fog Lamp Relay Ground

--

1

--

--

Front Fog Lamp Ground

--

1

--

--

1. Front Fog Lamps Malfunction

Circuit/System Description

The front fog lamp relay and front fog lamps are grounded at G105 at all times. When the body control module (BCM) is momentarily grounded when the front fog lamp switch is turned to the ON position. Battery voltage is then supplied to the coil side of the front fog lamp relay. The relay contacts now close supplying the front fog lamps with battery voltage turning them ON.

Conditions for Running the DTC

The battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

B2532

When the BCM receives a front fog lamp switch ON command and the front fog lamp relay control circuit is shorted to ground.

B2533

When the BCM receives a front fog lamp switch OFF command and the front fog lamp relay control circuit is shorted to voltage.

Action Taken When the DTC Sets

The front fog lamps will not operate or will remain ON at all times.

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.

Reference Information

Schematic Reference

Fog Lights Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

Front Fog Lamp Relay Control Circuit Test

  1. Ignition OFF, disconnect the front fog lamp relay.
  2. Verify a test lamp illuminates between the relay coil ground circuit terminal 86 and B+.
  3. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  4. Connect a test lamp between the relay coil control circuit terminal 85 and the ground circuit terminal 86.
  5. Ignition ON, command the front fog lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF.
  6. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
    If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  7. If all circuits test normal, test or replace the front fog lamp relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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