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 Descriptor
DTC B3600 08
- Passenger Compartment Dimming Request Signal Circuit Signal Invalid
Diagnostic Fault Information
Circuit/System Description
The instrument panel module (IPM) provides the instrument panel (I/P) dimmer switch with a 5-volt reference voltage and ground. The I/P dimmer switch is a potentiometer that varies the input signal voltage to the IPM. This input determines the intensity level of the back lighting illumination. When the IPM receives the input from the I/P dimmer switch, the IPM will send a serial data message to all control modules that have lamps capable of being dimmed, indicating the ON/OFF status and intensity level of the back lighting. The IPM will default to full intensity if the input from the I/P dimmer switch is not within the specified values.
Conditions for Running the DTC
Battery voltage must be between 9-16 volts.
Conditions for Setting the DTC
The IPM detects a short to ground, short to voltage, or an open/high resistance in the I/P lamp dimmer switch signal circuit after 450 milliseconds.
Action Taken When the DTC Sets
The IPM will default to full intensity if the input from the I/P dimmer switch is not within the specified values.
Conditions for Clearing the DTC
* The condition responsible for setting the DTC no longer exists.
* A history DTC will clear once 50 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 (Connector Views)
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 Testing
1. Ignition OFF, disconnect the harness connector at the I/P Dimmer switch.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the low reference circuit terminal 1.
• If the test lamp does not illuminate, test the low reference circuit for an open/high resistance.
3. Ignition ON, verify the scan tool Dimming POT A/D parameter is greater than 140 counts.
• If less than the specified range, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the IPM.
4. Install a 3-A fused jumper wire between the signal circuit terminal 2 and the low reference circuit terminal 1. Verify the scan tool Dimming POT A/D parameter is less than 30 counts.
• If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
5. If all circuits test normal, test or replace the I/P dimmer switch.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Instrument Panel Lamp Dimmer Switch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for IPM replacement, setup, and programming