Dash vent problems

[john shelman]

2003 Expedition- Ac works great...but when accelerating, the air stops coming from the dash ve ts and comes out the floor vents until you let off the gas. A mechanic checked under the hood, said the vacuum leak is in the dash, but he didn't want to mess with it. So, what am I looking for as the cause, where do I find it and how do I get to it? He talked like the entire dash would have to be taken loose. Surely there is some way to fix this without tearing the whole dash apart, which is way beyond my skill level.

 

[stamp11127]

It all depends on where the leak is. There is a vac line that comes through the firewall then to a manifold on the ac controls. It can leak there or in the control itself.