A8L Quattro Sedan V8-4.2L (BVJ) (2007)
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Ambient Light Sensor: Customer Interest
Lighting - Auto Headlamps Switch ON/OFF Erratically
94 Automatic headlight switches on and off without reason
94 10 12
2016808/3
May 5, 2010
Supersedes Technical Service Bulletin Group 94 number 08-35 dated November 13, 2008 for reasons listed below.
Affected Vehicles
Condition
^ The customer may report that the headlight turns on or off early or late when the light switch is in the Auto position.
^ After replacing the rain-light sensor G397 or after replacing the windshield, the automatic headlight may turn on or off without change of ambient
brightness.
The headlights operate normally if the light switch is in the On or Off position.
Technical Background
Possible causes:
^ Window damaged or dirty in the area of the sensor.
^ After repairing the windshield, the sensor is fitted without adhesive pad.
^ The rain/light sensor coding for the window is wrong, or the wrong windshield was installed.
^ Wiring damaged (plug or contact loose).
Production Solution
No change.
