B3600
DTC B3600
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 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/System Description
The instrument panel dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The body control module (BCM) supplies a 12 V reference to the backlight dimmer switch, which is part of the headlamp switch. When the backlight dimmer switch is placed in a desired brightness position, reference voltage is applied through the dimmer switch rheostat to the BCM. The BCM interprets this voltage signal, then applies a pulse width modulated (PWM) voltage to the LED dimming control 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
* The BCM detects a short to ground or open in the 12 V reference circuit.
* The BCM detects a short to ground or open in the instrument panel dimming signal circuit.
Action Taken When the DTC Sets
The Instrument Panel lamps are not illuminated.
Conditions for Clearing the DTC
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 Sunshade - Left
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, turn the parking lamps 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 X1 and X3 harness connectors at the K9 Body Control Module.
2. Ignition ON, test for less than 0.3 V between the signal circuit terminal 9 X1 and ground.
• If greater than the specified value, test the circuits listed below for a short to voltage. If the circuit tests normal, replace the S30 Headlamp Switch.
* Signal circuit terminal 9 X1
* 12 V reference voltage circuit terminal 4 X3
3. Ignition OFF, test for infinite resistance between the signal circuit terminal 9 X1 and ground.
• If less than infinite resistance, test the circuits listed below for a short to ground. If the circuit tests normal, replace the S30 Headlamp Switch.
* Signal circuit terminal 9 X1
* 12 V reference voltage circuit terminal 4 X3
4. Test for 7.4-7.9 kohms between the signal circuit terminal 9 X1 and the 12 V reference voltage circuit terminal 4 X3.
• If less than 7.4 kohms, test the signal circuit and the 12 V reference circuit for a short circuit. If the circuit tests normal, replace the S30 Headlamp Switch.
• If greater than 7.9 kohms, test the signal circuit and the 12 V reference circuit for an open/high resistance. If the circuit tests normal, replace the S30 Headlamp Switch.
5. Test for 3.7-4.1 kohms between the signal circuit terminal 9 X1 and the 12 V reference voltage circuit terminal 4 X3 while turning the thumbwheel for dimming up.
• If not the specified range, replace the S30 Headlamp Switch.
6. Test for 5.1-5.5 kohms between the signal circuit terminal 9 X1 and the 12 V reference voltage circuit terminal 4 X3 while turning the thumbwheel for dimming down.
• If not the specified range, replace the S30 Headlamp Switch.
7. If all circuits test normal, replace the K9 Body Control Module.
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