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Home >> Chevrolet >> 2020 >> Malibu LS >> Repair and Diagnosis >> External Pages >> Different car >> Section 96 (Wiper System And Washer System) >> Diagnostic Information and Procedures >> Rain Sensor Malfunction >> Circuit/System Description

Circuit/System Description

WARNING: This page is about a different car, the 2019 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.

For an overview of the component/system, refer to:Wiper/Washer System Description and Operation 

Circuit Description
Ignition circuit The output circuit is switched to 12 V to activate the component.
Serial Data circuit The serial data circuits are used to exchange information between the control modules.
Ground Chassis Ground
Component Description
K7 Body Control Module - Auxiliary The module controls various vehicle functions like lighting, central door locking, power windows, etc.
B177 Rain/Ambient Light Sensor Module The assembly has several functions:
  • In a rain sensor, the infrared light of an LED is beamed at the inside of the windshield at an angle of 45°. The outside of the windshield reflects most of the light back (again in an angle of 45°) to a light sensor. If the glass is wet, less light is reflected to the sensor because the refractive index of water is much smaller than the one of air. If the sensor detects water, it sends a bus message to the body control module, which will turn the wipers on.
  • The ambient light sensor is a light-sensitive diode. The brighter the ambient light, the higher the resistance.Photodiodes produce a small voltage when lit, which can make measuring its resistance with a multimeter difficult.
X51A Fuse Block - Instrument Panel The fuse block houses various fuses and relays.
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