Service Information

Volt

DTC B3600

Diagnostic Instructions

•	Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

•	Review Strategy Based Diagnosis for an overview of the diagnostic approach.

•	Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B3600 03: Passenger Compartment Dimming Request Signal Circuit Low Voltage

DTC B3600 07: Passenger Compartment Dimming Request Signal Circuit High Voltage

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Instrument Panel Dimmer Switch B+ Reference	B1395 03, B3600 03	B3600 03	1	B1395 07, 1
Instrument Panel Dimmer Switch Signal	B3600 03	B3600 03	B3600 07, 1	-
LED Backlight Dimming Control Terminal 8 X2	B2610 02	B2610 04, 1	B2610 01, 1	-
LED Backlight Dimming Control Terminal 9 X7	B2610 02	B2610 04, 1	B2610 01, 1	-
Instrument Panel Dimmer Switch Low Reference	1	1	1	--
Driver Information Centre Switch Ground	--	1	--	--
1. Interior Backlighting Malfunction

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

Conditions for Running the DTC

•	Battery voltage must be between 9-16 V.

•	Sidelights ON.

Conditions for Setting the DTC

DTC B3600 03

•	The BCM detects a short to ground or an open/high resistance in the instrument panel dimmer switch B+ reference circuit.

•	The BCM detects a short to ground or an open/high resistance in the instrument panel dimmer switch signal circuit.

DTC B3600 07

The BCM detects a short to voltage in the instrument panel dimmer switch signal circuit.

Action Taken When the DTC Sets

The interior backlighting defaults to full bright.

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 vehicle ON/OFF switch cycles have occurred.

Diagnostic Aids

The instrument panel dimmer switch B+ reference circuit is a low current circuit that will not illuminate a test lamp.

Reference Information

Electrical Information Reference

•	Circuit Testing

•	Connector Repairs

•	Testing for Intermittent Conditions and Poor Connections

•	Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

Vehicle OFF, disconnect the harness connector at the S16 Driver Information Centre Switch.
Vehicle in Service Mode, verify that a test lamp illuminates between B+ and the low reference circuit terminal 12.

⇒	If the test lamp does not illuminate, test the low reference circuit for a short to voltage or an open/high resistance.

Test for B+ between the B+ reference circuit terminal 11 and ground.

⇒	If less than the specified range, test the B+ reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.

Verify that a test lamp does not illuminate between the B+ reference circuit terminal 11 and ground.

⇒	If the test lamp illuminates, test the B+ reference circuit for a short to voltage. If the circuit tests normal, replace the K9 Body Control Module.

Verify the scan tool LED Backlight Dimming Command parameter is greater than 40%.

⇒	If less than the specified range, test the signal circuit terminal 10 for a short to voltage. If the circuit tests normal, replace the K9 Body Control Module.

Vehicle OFF, install a 3 A fused jumper wire between the B+ reference circuit terminal 11 and the signal circuit terminal 10.
Vehicle in Service Mode, verify the scan tool LED Backlight Dimming Command parameter is less than 40%.

⇒	If greater than the specified range, test the signal circuit terminal 10 for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.

If all circuits test normal, replace the S16 Driver Information Centre Switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•	Driver Information Display and Multifunction Switch Replacement

•	Control Module References for BCM replacement, programming and setup