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 instrument panel dimmer 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 signal circuit to the BCM. The BCM interprets this voltage signal, then applies a pulse width modulated voltage through the instrument panel 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
The ignition is ON.
Conditions for Setting the DTC
B1395 03
The BCM detects a voltage that is lower than 4.8 V on the instrument panel dimming 5 V reference circuit.
B1395 07
The BCM detects a voltage that is greater than 5.2 V on the instrument panel dimming 5 V reference circuit.
Action Taken When the DTC Sets
The instrument panel 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 (Electrical Diagrams)
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 instrument panel lamps should dim and then become full bright.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the S36 instrument panel dimmer switch.
2. Ignition OFF, test for less than 60 ohm between the low reference circuit terminal 10 and ground.
• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K9 BCM.
3. Ignition ON, test for B+ between the B+ circuit terminal 5 and ground.
• If less than the specified range, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
Note: The BCM will automatically put in a default Incandescent Dimming Duty Cycle Command setting of 50%. The next step will look for a brief change in the Incandescent Dimming Duty Cycle Command parameter from 50% to 5% - returning after 3 seconds to the 50% default setting.
4. Install a 3 A fused jumper wire between the signal circuit terminal 9 and the B+ circuit terminal 5. Verify the scan tool Incandescent Dimming Duty Cycle Command briefly drops to 5%, returning after 3 seconds to the 50% default value.
• 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 K9 BCM.
5. If all circuits test normal, replace the S36 instrument panel dimmer switch.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Dimmer Switch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming