The electric pump in VW / Audi engine compartments is for factory cruise
control only.  The "bi-pressure" two-way pump in a VW/ Audi trunks
(inside a foam package for quiet operation) is for vacuum-operated power
door locks.  Neither of these will work with the  aftermarket cruise
control.

Mike B.

On 11/4/2012 7:23 AM, Larry Alofs wrote:
> If you are installing or troubleshooting a vacuum powered system you should
> realize that late model vanagons have a vacuum pump rather than stealing
> from the intake manifold.  I owned a '91 for a number of years before I
> noticed the pump and realized what it was.  I have found the same pump (in
> the trunk!) of Jettas of similar vintage.
>
> Larry A.
>