Retro fitting auto dimming rear view mirror

[Mav190sline]

Hi chaps/chapesses

As title says, has anyone done this/know how to do it. Found one in the garage and thought I'd make use of it.
Car is 2001 facelift s3. I have removed the interior light to see if there is a spare plug for it on the wiring loom but to no avail, just wondering if it can be done and thought I'd ask the experts

Thanks for your time

Mark

 

[@udi A3]

Use the ****ing search button!!!!

 

[@udi A3]

Admitingly I should have practiced what I preach...