2010 Cadillac CTS Sedan AWD V6-3.6L Page 368

2010 Cadillac CTS Sedan AWD V6-3.6L Page 368

dimmer switch provides a voltage signal that will increase as the brightness of the lights are increased and decrease as the brightness of the lights

are decreased. The body control module (BCM) provides a low reference signal and a B+ voltage reference to the I/P dimmer switch. When the I/P

dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the I/P dimmer switch through the I/P dimmer switch

signal circuit to the BCM. The BCM interprets the signal and applies the dimmed voltage to the I/P lamps supply voltage circuit and the interior

backlighting components dim to the requested level.

Conditions for Running the DTC

Battery voltage must be between 9-16 V.

Conditions for Setting the DTC

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The DTC will set for the following conditions:

* The BCM detects a short to ground in the I/P dimmer switch voltage reference circuit.

* The BCM detects a short to ground in the I/P dimmer switch signal circuit.

* The BCM detects a short to ground or an open/high resistance in the BCM 1 fuse B+ circuit.

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The BCM detects a short to voltage in the I/P dimming voltage reference circuit or the vehicles system voltage exceeds the normal operating range

of 16 V.

Actions Taken When the DTC Sets

* The I/P dimmer switch will not operate.

* The I/P dimming lamps will not illuminate.

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 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)

Connector End View Reference

Component Connector End Views (See: Diagrams/Connector Views)

Description and Operation

Interior Lighting Systems Description and Operation (See: Lighting and Horns/Description and Operation/Interior Lighting Systems Description

and Operation)

Electrical Information Reference

* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit Testing/Circuit Testing)

* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Connector Repairs/Connector Repairs)

* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit

Testing/Testing for Intermittent Conditions and Poor Connections)

* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Wiring Repairs/Wiring Repairs)

Scan Tool Reference

Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information

Circuit/System Verification

Ignition ON, cover the ambient light sensor, vary the interior lamp dimming switch from dim to full bright. The lamps should dim and then become

full bright.

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 ground circuit terminal 10.

瀚慖f the test lamp does not illuminate, test the ground circuit for an open/high resistance.