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Tech Article

Control module differences between static and dynamic headlight range control systems

Last Updated: 08/12/2020
Parts Group: Control module
This article discusses the Control module (Headlight range control) for the C5 A6 & S6 and the D2 A8 & S8 with the main focus being on differences between static and dynamic headlight range control systems. If you're not here for the technical analysis but would rather buy a used unit from us, guaranteed to work and fit, then please select the link below.
According to OEM schematics, there are two VAG option codes for headlight range control on the C5 A6:  8Q2 (static) and 8Q3 (dynamic).  We only currently have first hand experience with 8Q3 cars.  These 8Q3 cars we're familiar with include the post face lift D2 A8 & S8 (2000 on) and the post face lift C5 A6 & S6 (2002 on).  
According to schematics the pre face lift C5 apparently had both 8Q2 and 8Q3 as options but post face lift C5 did away with the use of 8Q2 entirely, as did the D2.  You may see pre face lift C5 compatibility for the 8Q3 control module but that's only part of the story, for it is specifically meant for vehicles with dynamic headlight range control only.  The easiest way to tell these two apart?  The OEM part number.  The 8Q3 dynamic control module is 4Z7907357 while the 8Q2 static control module is 4B0907357.
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