I recently was working with a similar 4 pin relay with my A8 (2007 D3). Specifically the relay that controls the air suspension compressor. So i've learnt how they work (or reminded myself of that which I had forgotten from school days).
This looks really interesting and cool!
Someone please shout up if they manage it? I have my boot liner removed as waiting for a replacement boot lid tail light (the old one managed to get a crack in it somehow!), so I'm tempted too!
