Originally Posted by VW TANK
another person told me its under the airbox....before i got tearing things apart, is this true?
That is true for 2001~2003 and maybe some other later years too.
To save some guesswork, it might be a good idea to follow the plastic vacuum line from the intake manifold to the passenger side engine bay. Ultimately, it should lead you right to the reservoir. For 98~2000, I think you'll find it between the fender and the plastic inner fender on that side.