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 Instructionsprovides an overview of each diagnostic category.
DTC Descriptors
DTC B1395 03
- Device Voltage Reference Output 1 Circuit Voltage Below Threshold
DTC B1395 07
- Device Voltage Reference Output 1 Circuit Voltage Above Threshold
Diagnostic Fault Information
Circuit/System Description
Voltage for the interior backlighting components and stop lamp switch activation signal is supplied from the body control module (BCM). The BCM applies a voltage reference through the instrument panel (I/P) dimming voltage reference circuit to the interior lamp dimming switch, which is part of the headlamp switch. When the dimming switch is placed in the desired position, the dimmed voltage setting is applied from the interior lamp dimming switch through the I/P dimming control circuit to the BCM. The BCM then applies the dimmed voltage to the I/P lamps supply voltage circuit and they dim to the correct level.
The stop lamp switch is also supplied voltage on the same circuit for a stop lamp OFF signal to the BCM. When the stop lamp switch is activated the voltage signal circuit to the BCM is opened prompting the BCM to illuminate the stop lamps.
Conditions for Running the DTC
* Battery voltage must be between 9-16 V.
* Ignition must be ON.
Conditions for Setting the DTC
B1395 03
The BCM detects a voltage that is lower than 0.33 V on the I/P dimming voltage reference circuit.
B1395 07
The BCM detects a voltage that is greater than 4.97 V on I/P dimming voltage reference circuit.
Action Taken When the DTC Sets
* The I/P lamps are dim or not illuminated.
* The I/P lamps will not dim.
* The stop lamps are always ON.
Conditions for Clearing the DTC
* The conditions for setting the DTC are no longer present.
* A history DTC clears after 100 malfunction-free ignition cycles.
* The BCM receives the clear code command from the scan tool.
Reference Information
Schematic Reference
* Interior Lights Dimming Schematics Interior Lights Dimming Schematics
* Exterior Lights Schematics Exterior Lights 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 Relearningfor scan tool information
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the headlamp and panel dimmer switch.
2. Ignition OFF, verify that a test lamp illuminates between the ground circuit terminal 8 and B+.
• If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Ignition ON, verify the scan tool Dimming Control Signal parameter is less than 0.1 V.
• If greater than the specified range, test the signal circuit terminal 13 for a short to voltage. If the circuit tests normal, replace the BCM.
4. Ignition ON, test for 12 V between the I/P dimming voltage reference 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 tests normal, replace the BCM.
5. Install a 3 A fused jumper wire between the signal circuit terminal 13 and the voltage reference circuit terminal 15. Verify the scan tool BCM Dimming Control Signal parameter is greater than 2.6 V.
• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
6. If all circuits test normal, test or replace the headlamp and panel dimmer switch.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Headlamp Switch Replacement
* Control Module References Programming and Relearningfor BCM replacement, setup, and programming