B2527

DTC B2527

Diagnostic Instructions

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

DTC Descriptor
DTC B2527
^ Front Fog Lamps Circuit Low

Circuit/System Description

The body control module (BCM) monitors the front fog lamp switch signal circuit in order to determine when the fog lamp relay is to be energized. When the BCM senses that the front fog lamp switch signal circuit is grounded momentarily when the switch is turned on, the BCM energizes the fog lamp relay by grounding the fog lamp relay control circuit.

Conditions for Running the DTC

The battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

The front fog lamp switch signal circuit is shorted to ground for 15 minutes.

Action Taken When the DTC Sets

The front fog lamps will be inoperative.

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 (Wiring Diagram Index)
Connector End View Reference

Component Connector End Views (Component Connector End Views)
Description and Operation

Exterior Lighting Systems Description and Operation (Exterior Lighting Systems Description and Operation)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Control Module References) for Scan Tool Information

Circuit/System Verification

Ignition ON, observe the scan tool front fog lamp switch parameter while turning the front fog lamp switch on and off. The reading should change between on and off.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector X4 at the turn signal/multifunction switch.
2. Ignition ON, verify the scan tool front fog lamp switch parameter is off.

• If not the specified value test the front fog lamp switch signal circuit terminal E for a short to ground. If the circuit tests normal replace the BCM.

3. If all circuits test normal, test or replace the headlamp switch.

Component Testing

1. Ignition OFF, disconnect the harness connectors at the turn signal/multifunction switch.
2. Test for infinite resistance between the front fog lamp switch signal terminal E X4 and the low reference terminal F X4 with the switch in the off position.

• If not the specified value, replace the turn signal/multifunction switch.

3. Test for less than 1 ohm between the front fog lamp switch signal terminal E X4 and the low reference terminal F X4 with the switch in the on position.

• If greater than the specified range, replace the turn signal/multifunction switch.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Headlamp Switch Replacement (Service and Repair)
* Control Module References (Control Module References) for BCM replacement, programming, and setup