So I've been checking all my vacuums like everybody and couldn't find any breaks. So I decided to change the check valve off engine and one behind hvac controls. Drive to work this morning and it switches to top vent even more now then it did before. Wtf

 

They need to be installed in the right direction.

 

I installed the same way they came out. Which way is right direction I'll check when I get home later?

 

I reverse the check valves and it only came out of the defrost vent

 

Should be arrows on the valves indicating direction of flow. Those should be pointing toward the motor.

Check the line going to the vacuum reservoir, and the reservoir itself as well.

 

I did one on engine and one behind hvac controls. There's more. The one by reservoir (behind passenger headlight) I didn't see check valve

 

There isn't a valve there, but, if there is a leak, your vents still won't work right.

 

Did you test the check valves? Blow into them in both directions, air should only move one way.