Vent Selector

[AxeGrinder101]

Hi all.
Car is an 01 WS6.
A/C blows cold air, all 4 fan speeds work.
The problem is the air only comes out underneath the dash, towards your feet, and not out the top vent. Air also comes out of the defroster vents.
Toggling thru the vent selector switch does nothing.
Been searching the net for a solution and it would seem it is a vacuum problem.
Vent doors are vacuum operated and somehow there must be a vacuum leak somewhere preventing them to work properly?
The question then is, under the hood, is there an accessible vacuum canister or which hoses to check for possible vacuum leak?
Any info is appreciated.
Thanks

[gnomee]

Oh man I'm glad someone had this problem so I can share It took me quite a while to get help myself when it first happend. Under the hood on the passenger side there is two little vaccum lines that connect with a little plastic T thing. It gets hot and cracks. I used to change it once a year for some reason I would just keep melting. I plugged the holes and put some off the shelve super epoxy all around the plastic. Been 2 years and still has not melted again. I'm sure you can find the hose i'm talking about there the small plastic kind. If not I can get you some pics, its right up top though.

[AxeGrinder101]

Found the plastic T and it is in good condition.
3 thin hoses are hooked up to it and all are in good shaped and plugged in securely.
I traced the single thin hose that goes thru the firewall passenger side.
I disconnected it from the T and hooked up a vacuum gauge into the T.
Gauge reads nothing.
Would you happen to know how much vacuum the line should have, if any?
And if it does, where is the source?

I also checked the selector switch itself. It works because the a/c turns on and off and blows cold air, it just would not come out of the top vents.

Hayne's manual has nothing on this particular problem.
Any ideas?

Thanks

[mo gomez]

youre a.c. vaccuum line gets its source at the very back of the intake manifold if you have zero inches of vaccuum continue to trace the plastic line to the rear of the intake and make sure it is not broken or disconnected at the source, once youre line is reconnected or repaired youre air will stop blowing on defrost only. to confirm this is youre only problem install a inexpensive piece on vaccuum hose that is the proper size and hook directly from youre underhood passenger vaccuum port to the intake and start and idle the vehicle to verify that it is now blowing out of the vent and you will know this is youre only problem. now all you have to do is repair the remainding line you disconnected and bypassed to perform this check and youre brand new again.

[AxeGrinder101]

Thank you Mo Gomez.
Fixed the problem yesterday.
Yes, the hose was disconnected from the back of the intake manifold (most likely happened while changing the driver side spark plugs).
Plugged it back up and it's nice to have cold air blowing again.
Just in time with the Florida weather heating up already.

I see you're in Coral Springs, I'm often there visiting my nephew.
Well anywho, thanks again for sharing your knowledge.