What's this button for??

[Gaz78]

As above, what's the switch I've circled in blue do on my 2007 A3?.....I've pushed it but can't see any changes anywhere!

 

[LEE69]

Coming home lights. Put the light switch to auto, and the headlights stay on (mines 10 seconds) when locking or unlocking if it's dark

 

[Gaz78]

Ah right......Thanks mate

Gaz