Nissan Stagea Rs Four Series Ii

[kem]

I got a series 2 stagea, but mine came with a series 1 owners manual, so thats why i wanna ask anyone who know what the dash button next to the demister button actually does, it looks like a 4wd driveline with an "S" symbol in the center diff...

Aslo my electric boot stopped workin, and the doors open light is always on, even when the doors are all cloed properly. Has this happened to anyone with an electric closing boot? I rekon this may have happened cause i put a 1400watt sub at the back, too much bass ruined the mechanism maybe? Anyhow..