What is the one wire on the outside of the ignition switch do? it came unplugged while taking off my dash and I have no idea what it is for?? its black and it to the left of the key insert. Please help, thanks in advance ))

 

It is probably for key in switch alarm. [8D]

 

its unplugged but still starts and runs, do I need to plug it back in?

 

It is probably just to let you know or remind you you left key in switch when you open door. Does that work?