Just buy a tube and slip both ends into the tube and there you go. Any vac leak like that can jack up the HVAC controller. Happened to my Expy right after I first got it. Vac line disconnected by the firewall, plugged it back in and have not had a problem since.
2000 Mustang GT Steeda build #48. Bolt ons, suspension, Novi 2000.
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.