PCV valve won't have anything to do with your vents. There is a check valve or two in the vacuum lines between the intake, and the firewall. Check those.

 

So whats pcv do?

 

Positive Crankcase Ventilation. (as opposed to "perhaps crankcase ventilation"....) Circulates air thru the crankcase, so get rid of blowby gases, that make it past the piston rings. Draws a slight vacuum on the crank case, to aid in ring seal. It is an important system, that you want working correctly.

Check the Wild Vents thread in the FAQ section to fix your vents switching issues.