Whatever you do DON'T touch it, its the button for the ejector seat! Unfortunately I have no idea, may be worth contacting the seller you purchased it from and enquire? Or switch your bluetooth on, on your phone and see if it finds any devices?
Well, I have done a bluetooth scan, nothing comes up. I have rang the previous owner and he didnt know either The wire goes into the dash and I dont want to start ripping it open. Was hoping someone may spot it and know.
Perhaps its a 8ullsh1t detector, green means truth !