So I ordered a new Four Seasons vacuum control valve because my old one was hissing up a storm but it would still select the proper blower mode. I hooked the tubes up to the new one and turned the dial to the right place as I moved the selector switch on the control unit and everything worked great. I held it it place without the screws making sure to push that peg into the little vertical channel that keeps it where it should be as the selector switch selects and everything worked great. I screwed the screws in as I held it in place with max a/c selected so I could feel the vent blowing on me the whole time. I moved the switch side to side and everything started hissing and blowing through the defrost vents only. I did this for 2 hours probably taking it off and putting it back on and couldn't figure out what the heck was happening...it wouldn't work while fully installed. I'm thinking of just fixing my old valve with the bolt/nut trick and seeing if that does it and bringing this silly new one back to Oreilly. Does anyone have any thoughts?

 

FYI I fixed the old valve and put it back in and everything works great!

 

Bolt and nut trick: