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 Instructionsprovides an overview of each diagnostic category.
DTC Descriptors
DTC B3600 03
- Passenger Compartment Dimming Request Signal Circuit Voltage Below Threshold
DTC B3600 07
- Passenger Compartment Dimming Request Signal Circuit Voltage Above Threshold
Diagnostic Fault Information
Circuit/System Description
Voltage for the interior backlighting components is supplied from the body control module (BCM). The BCM applies a voltage reference through the 12 V reference circuit to the headlamp and panel dimmer switch. When the dimming switch is placed in the desired position, the dimmed voltage setting is applied from the headlamp and panel dimmer switch through the instrument panel (I/P) lamp dimmer switch signal circuit to the BCM. The BCM then applies the dimmed voltage to the lamp supply voltage circuits and they are dimmed to the correct level.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
B3600 03
The BCM detects a voltage that is lower than 0.10 V on the I/P lamp dimmer switch signal circuit.
B3600 07
The BCM detects a voltage that is higher than 4.97 V on the I/P lamp dimmer switch signal circuit.
Action Taken When the DTC Sets
The I/P lamps are not illuminated.
Conditions for Clearing the DTC
The BCM clears this code from current when the fault is removed from the system.
Reference Information
Schematic Reference
Interior Lights Dimming Schematics Interior Lights Dimming 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 Verification
Ignition ON, headlamp switch to HEAD, vary the interior lamp dimming switch from dim to full bright. The I/P lamps should dim and then become full bright.
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 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