What problem is your Uncle having? As far as having a wiring schematic, I don't think too many people have those. VW has a publishing agreement with Robert Bentley Publishing out of Cambridge, MA. Currently, the only manual available is in CD form. I haven't bought one yet since the car is still under warranty.
Is your Uncle looking to disable the DRLs?

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1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member