Freightliner air pressure switches behind dash

Hi.

I had an air pressure switch blow out behind the dash, the issue is, when I pulled the dash out, there is 2 switches that the wires have come off, I am assuming it doesn't matter which wires goes on which switch, and it doesn't matter which wires go on each each (just a black and grey wire on each switch)

For my info, what do these switches do? They look like they are on the same air rail.

Cheers.