Captiva

DTC B2645

The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary depending on outside lighting conditions. The body control module (BCM) provides a 10-volt reference signal to the ambient light sensor. The BCM monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or automatic lamp control (ALC) when the headlamp switch is in the AUTO position. In daylight conditions, the BCM will command the DRLs ON. In low light conditions, when the headlamps switch is in AUTO position, the BCM will command the dipped beam headlamps ON.

Battery voltage must be between 9-16 volts.

B2645 03

The DTC will set when the BCM detects voltage is low in the ambient light sensor signal circuit.

B2645 07

The DTC will set when the BCM detects voltage is above 10 volts in the ambient light sensor signal circuit

When DTC B2645 03 or B2645 07 is present, the ALC will default to ON.

Schematic Reference

Exterior Lamps Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the ambient light sensor.
2. Ignition ON, monitor the Ambient Light Sensor parameter in the BCM data list with a scan tool.

⇒	If the scan tool parameter is less than 7 volts, locate and repair an open, high resistance, or short to ground in the ambient light sensor signal circuit, or replace the ambient light sensor.

⇒	If the scan tool parameter is greater than 10.5 volts, locate and repair a short to voltage in the ambient light sensor signal circuit.

3. If circuits test OK, replace the BCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.