Lighting

DTC B1395

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 Descriptors
DTC B1395 03
- Control Module Voltage Reference Output 1 Circuit Low Voltage

DTC B1395 07
- Control Module Voltage Reference Output 1 Circuit High Voltage

Diagnostic Fault Information





Circuit/System Description

The body control module (BCM) supplies a voltage reference through the instrument panel dimming voltage reference circuit to the interior lamp dimmer switch, which is part of the headlamp switch. When the dimmer switch is placed in a desired brightness position, reference voltage is applied through the dimmer switch rheostat and the instrument panel lamps dimmer switch signal circuit to the BCM. The BCM interprets this voltage signal, then applies a pulse width modulated (PWM) voltage through the instrument panel lamps supply voltage circuit and the LED dimming supply circuit to all related interior lamps, illuminating them to the desired level of brightness.

Conditions for Running the DTC

* Ignition ON
* Park lamps ON

Conditions for Setting the DTC

B1395 03

The BCM detects a voltage that is lower than 11.8 V on the instrument panel dimming voltage reference circuit.

B1395 07

The BCM detects a voltage that is greater than 12.2 V on instrument panel dimming voltage reference circuit.

Action Taken When the DTC Sets

Interior lights dimming is disabled. All interior lights are at full intensity.

Conditions for Clearing the DTC

* The condition for setting the DTC is no longer present.
* A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Reference Information
Schematic Reference

Interior Lights Dimming Schematics (Interior Lights Dimming Schematics)
Connector End View Reference

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

Interior Lighting Systems Description and Operation (Interior Lighting Systems)
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 (Programming and Relearning) for scan tool information

Circuit/System Verification

Ignition ON, cover the ambient light sensor. Vary the interior lamp dimming switch from dim to full bright. The lamps should dim and then become full bright.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the S30 Headlamp Switch.
2. Ignition ON, test for 11.8-12.2 V between the 12 V reference circuit terminal 15 and ground.

• If greater than the specified range, test the 12 V reference circuit for short to voltage. If the circuit tests normal, replace the K9 Body Control Module.
• If less than the specified range, test the 12 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.

3. If all circuits test normal, replace the S30 Headlamp Switch.

Repair Instructions

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

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