2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 478
Diagnostic Fault Information
Circuit/System Description
The body control module (BCM) supplies battery positive voltage 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 to the BCM. The BCM interprets this voltage signal,
then applies a pulse width modulated (PWM) voltage to the LED dimming supply 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
B1405 03, B1529 03, or B257B 03
The BCM detects less than 0.3 V on the dimmer switch signal circuit.
B1405 07, B1529 07, or B257B 07
The BCM detects a voltage greater than 12.2 V on dimmer switch signal circuit.
Action Taken When the DTC Sets
The BCM will not dim or illuminate any LED backlighting supplied by the backlight lamp control circuits.
Conditions for Clearing the DTC
* The condition responsible for setting the DTC no longer exists.
* A history DTC will clear once 100 consecutive fault free ignition cycles have occurred.
Reference Information
Schematic Reference
* Interior Lights Dimming Schematics (See: Diagrams/Electrical Diagrams/Lighting and Horns/System Diagram/Interior Lights Dimming
Schematics)
* Steering Wheel Secondary/Configurable Control Schematics (See: Accessories and Optional Equipment/Diagrams/Electrical
Diagrams/Steering Wheel Secondary/Configurable Control Schematics)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views/Connector End Views By Name)
Description and Operation
Interior Lighting Systems Description and Operation (See: Lighting and Horns/Description and Operation/Interior Lighting Systems)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
