2010 Explorer No A/C from front vents

[KevN2009]

I know there's been several threads about this, but I replaced the check valve in the engine compartment with no luck. How can I troubleshoot this as a vacuum issue, or something broken? When this first happened, I could get the vents working sometimes by moving back and forth between defrost and max air, and finally it was blowing thru the front vents while I had it on defrost. Then my son messed with it and it went back to not blowing. Also sometimes if I hit the brakes hard it starts blowing thru the front vents temporarily. Ideas?

 

[KevN2009]

I found out it was the broken plastic lever for the door actuator. Fixed liked in this video

 

[EXFAN]

Check the small vacuum hose - passenger side top of firewall that supplies vacuum to the inside blendoor. Mine which was leaking causing the same problem. When you hit the brakes, you are also closing/letting up on the throttle which causes engine vacuum to temporarily jump higher than normal driving. This could cause a leaky hose to supply enough vacuum for a short time. I'm curious when the dash vents blow AC while braking, whether it keeps on working or goes away after a few seconds. If the latter, check that hose first and if OK, others under the dash (if any) that supply vacuum to the blendoor. After that, check the fitting on the YT video in the previous post.