The air will only blow through the vents

Thank you! Can you post a link to the video?

Just enter this in the youtube search bar : replace ETAC control on 05 merc grand marquis.... Or crown vic either one. YOU do the searching! ......AH W.T.H. Here you go: http://m.youtube.com/watch?v=S2Q0SvvE-gg Reverse procdure to install. ★ Now, once the unit is removed the system can be tested with a mityvac to be 100% sure it is the problem. That is where you need skills. Or a mechanic!