What is this switch for in the glovebox please?

I have a switch with a AUX wire coming out of it can anyone tell me what its for please?? I can't find any info at all on it.....i thought was to plug in a mobile phone or ipod ect but nothing happens. I've tried to add a pic but it wont work for some reason.

Car is a mk3 espace.

Thank you.

What is this switch for in the glovebox please?