Lighting

DTC B1395

Diagnostic Instructions

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

DTC Descriptors
DTC B1395 03
- Voltage Below Threshold

DTC B1395 07
- Voltage Above Threshold

Diagnostic Fault Information





Circuit/System Description

The body control module (BCM) supplies a voltage reference through the instrument panel (I/P) 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 I/P lamps dimmer switch signal circuit to the BCM. The BCM interprets this voltage signal, then applies a pulse width modulated (PWM) voltage through the I/P 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

Battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

B1395 03

The BCM detects a voltage that is lower than 9 volts on the I/P dimming voltage reference circuit.

B1395 07

The BCM detects a voltage that is greater than 14 volts on I/P dimming voltage reference circuit.

Action Taken When the DTC Sets

The I/P lamps are not illuminated.

Conditions for Clearing the DTC

* The condition responsible for setting the DTC no longer exists.
* 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 Views)
Description and Operation

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

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the headlamp switch.
2. Ignition ON, test for B+ between the reference voltage circuit terminal 15 and ground.

• If less than the specified value, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit test normal, replace the BCM.

3. Ignition OFF, disconnect the X3 harness connector at the BCM.
4. Ignition ON, test the 12 volt reference circuit terminal 12 for a short to voltage.
5. If all circuits test normal, replace the 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