AC blows out floor and defrost vents?

[davidijaxson]

Originally Posted by CamP

I've read that if both the cruise control doesn't work and the dash vents don't blow, the cause is either the vacuum check valve under the plenum is bad or the vacuum line to it is disconnected. Both use a common vacuum line that originates on the right side of the plenum.

I have a buddy that?s a pretty decent mechanic. We have checked everything external to the plenum. Or at least I believe we have. I am guessing next step Is to locate a new check valve and then remove the plenum. Or is there some type of test you can perform on the check valve to determine If it is bad?