No ac

Hey guys so I bought this crown Vic a couple months ago and the ac didn't work. I already tried pulling out the passenger air bag and flipping the blend door manually but it was already stuck on the ac side, I also tried charging the system which resulted in almost a rough idle. Before I go to a mechanic I turned to here because I noticed what seems to me as a white vacuum line that goes through the fire wall near the gas pedal but it isn't connected to anything In the cabin OR the enigine bay I've searched for where it may go with no luck. If anyone can help or possibly provide pictures as to where it may go it would be very appreciated. Thanks!