2010 Cadillac Truck SRX FWD V6-3.0L Page 588

2010 Cadillac Truck SRX FWD V6-3.0L Page 588

Circuit/System Description

The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between

1.4-4.5 V depending on outside lighting conditions. The body control module (BCM) monitors the ambient light sensor signal circuit to determine

if outside lighting conditions are correct for either daytime running lights or automatic lamp control when the headlamp switch is in the AUTO

position. In daylight conditions the BCM will command the daytime running lights ON. During low light conditions the BCM will command the

low beam headlamps ON.

Conditions for Running the DTC

Ignition ON

Conditions for Setting the DTC

B2645 03

The BCM detects a short to ground on the ambient light sensor signal circuit.

B2645 07

The BCM detects greater than 5 volts on the ambient light sensor signal circuit.

Action Taken When the DTC Sets

The automatic headlamps will malfunction.

Conditions for Clearing the DTC

* The DTC will be current for as long as the fault is present.

* When the fault is no longer present, the DTC will be a history DTC.

* A history DTC will clear after 50 ignition cycles.

Reference Information

Schematic Reference

Exterior Lights Schematics (See: Diagrams/Electrical Diagrams/Lighting and Horns/System Diagram/Exterior Lights Schematics)

Connector End View Reference

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

Description and Operation

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

Procedures/Connector Repairs/Connector Repairs)

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

Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)

* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring

Repairs/Wiring Repairs)

Scan Tool Reference

Control Module References (See: Testing and Inspection/Programming and Relearning)

Circuit/System Verification

Ignition ON, observe the scan tool Ambient Light Sensor parameter. The reading should be between 1.4-4.5 V and change with ambient light

changes.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the B10B ambient light/sunload sensor.