avantiblue

Hi,
I own an Audi A3 2005 1.6 sport - 8P model
Recently got many issues at the same time:-

Dashboard lights flickering intermittently
Wiper washer fluid has stopped working, wipers work fine
Passenger door has stopped opening

I had the car checked where they put it on a computer and they have told me that my central convenience module needs replacing, and then the car will need recoding again to the this module.

My question is, where is the module located, and could I get a second hand module from another vehicle and have it recoded to my car?

Any help would be appreciated as I am a new member to the site.

Thanks
Imran