Diagnostic Instructions

DTC Descriptors

DTC B1395 03: Device Voltage Output 1 Circuit Voltage Below Threshold

DTC B1395 07: Device Voltage Output 1 Circuit Voltage Above Threshold

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Body Control Module (BCM) B+ Terminal 3 X3	B1395 03, B3600 03	B1395 03, B3600 03	--	--
I/P Dimmer Switch B+ Voltage Reference	B1395 03, B3600 03	B3600 03	--	B1395 07
I/P Dimmer Switch Signal	B3600 03	B3600 03	1	--
1. Interior Backlighting Malfunction

Circuit/System Description

The instrument panel (I/P) lamp dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The I/P dimmer switch provides a voltage signal that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The body control module (BCM) provides a low reference signal and a B+ voltage reference to the I/P dimmer switch. When the I/P dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the I/P dimmer switch through the I/P dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies a pulse width modulated (PWM) voltage to the I/P lamps supply voltage circuit and the interior backlighting components dim to the requested level.

Conditions for Running the DTC

Battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

B1395 03

The DTC will set for the following conditions:

B1395 07

The DTC will set when the BCM detects a short to voltage in the I/P dimming voltage reference circuit or the vehicles system voltage exceeds the normal operating range of 16 volts.

Actions Taken When the DTC Sets

Conditions for Clearing the DTC

Reference Information

Schematic Reference

Interior Lights Dimming Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Interior Lighting Systems Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, observe the scan tool Dimming Control Reference voltage. The reading should display 2.5 volts or greater.

Circuit/System Testing

I/P Dimmer Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the headlamp switch.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 8.

⇒	If the test lamp does not illuminate, test the ground circuit for an open/high resistance.

3. Ignition ON, test for B+ between the 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.

4. Install a 3A fused jumper wire between the signal circuit terminal 13 and the voltage reference circuit terminal 15. Verify the scan tool Dimming Control Signal parameter is greater than 2.5 volts.

⇒	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.

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

I/P Dimming Control Malfunction

1. Ignition OFF, disconnect the X3 harness connector at the BCM.
2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 3 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

3. If all circuit tests normal, replace the BCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.