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Home >> Pontiac >> 2001 >> Aztek Base, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 710 (Lighting Systems) >> Diagnostic Information and Procedures >> DTC B2647: Ambient Light Sensor Signal Reference Circuit Open Or Shorted >> Circuit Description
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Circuit Description

WARNING: This page is about a different car, the 2002 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.

The ambient light sensor indicates the light level to control the automatic headlamps and park lamps. The body control module (BCM) provides a 5 volt reference signal to the ambient light sensor through the ambient light sensor signal reference circuit. The BCM receives the modified voltage from the ambient light sensor through the ambient light sensor signal return circuit. A low voltage, under 1.5 volts signals a dark condition to the BCM and vice versa.