I just got a 2008 A4 Avant (6-speed manual Quattro). It has the basic rear view mirror.

I am thinking of adding the auto-dim mirror with compass. I know when putting a similar mirror in a B6, you plug in the connector at the dome light, and then you have to splice in a power wire down by the driver footwell.

So my question is, when upgrading a B7 car from a basic mirror to a B7 auto-dim compass mirror, do you also have to splice the footwell wire? Or should it work by just connecting the plug at the dome light?