For 1990-2009 cars

### 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 B2530 02 : Front Fog Lamps Control Circuit Short to Ground
DTC B2530 05 : Front Fog Lamps Control Circuit Open or Short to Voltage

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Front Fog Lamp Relay Switch B+ | 1 | 1 | 1 | --
Front Fog Lamp Relay Control | B2530 02 | B2530 05 | B2530 05 | --
Front Fog Lamp Voltage Supply | 1 | 1 | 1 | --
Front Fog Lamp Switch Signal | 1 | 1 | -- | --
Front Fog Lamp Relay Ground | -- | 1 | 1 | --
Fog Lamp - LF Ground | -- | 1 | 1 | --
Fog Lamp - RF Ground | -- | 1 | 1 | --
Front Fog Lamp Switch Ground | -- | 1 | 1 | --
1. Front Fog Lamps Malfunction

### Circuit/System Description

When the front fog lamp switch is placed in the ON position, ground is applied through the front fog lamp switch signal circuit at G300 to the body control module (BCM). The BCM applies battery voltage through the front fog lamp relay control circuit to the coil side of the front fog lamp relay. Battery voltage is applied at all times from the FOG LAMP fuse to the switch side of the front fog lamp relay. When the relay coil is energized, the relay switch contacts close and allow battery voltage to be applied from the FOG LAMP fuse, through the relay switch contacts, to the front fog lamps. Ground for the front fog lamps is applied at all times at G101 for the left front fog lamp and G102 for the right front fog lamp. G102 also serves as ground for the coil side of the front fog lamp relay. For more detailed information concerning fog lamp operation refer to Exterior Lighting Systems Description and Operation .

### Conditions for Running the DTC

Battery voltage must be between 9-16 volts.

### Conditions for Setting the DTC

#### B2530 02

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

#### B2530 05

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

### Actions Taken When the DTC Sets

#### B2530 02

When this DTC is present, the front fog lamps will not operate when the park lamps are ON and the front fog lamp switch is active.

#### B2530 05

When this DTC is present, the front fog lamps and/or the front fog lamp indicator will be ON at all times or will not operate.

### Conditions for Clearing the DTC

• | The condition responsible for setting the DTC no longer exists.

• | You issue a scan tool CLEAR DTCs command.

• | A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

### 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 Testing

1. Ignition OFF, disconnect the front fog lamp relay.
2. Ignition OFF, test for less than 1.0 ohm of resistance between the front fog lamp relay ground circuit terminal 85 and ground.

⇒ | If greater than the specified range, test the ground circuit for an open/high resistance.

3. Connect a test lamp between the front fog lamp relay control circuit terminal 86 and ground.
4. Command the front fog lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒ | 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 open/high resistance. If the circuit tests normal, replace the BCM.

5. 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.

• | Underhood Electrical Center or Junction Block Replacement

• | Relay Replacement

• | Control Module References for BCM replacement, setup, and programming