I'm having a problem with the air vents in my car.

No matter which setting I have the fans for, air is only coming out of the defroster on top of the middle of the dash, as well as the side ones, and the floor.

I replaced the "setting switch" and the piece behind it where the vacuum hoses push into (3rd/last switch to the right). No dice. I'm still having the same problem.

Anyone have any suggestions?

Check the A/C vacuum check valve, passenger side. Make sure the valve itself isn't cracked or the lines to it.
Vacuum check valve

What he said

Thanks for the info. Which part is the valve? Is it the part on the left that's shaped like an "L"? The metal thing?

Right under the 90* elbow fitting. It's plastic. 3 plastic lines connecting to it.

Ah, I gotcha. The thing that looks like the plugwire boot.

Thanks. I'll have to give that a look tomorrow. If it's not that, any other ideas?

most autoparts places dont carry a 3 way check valve... but a two way will work just fine, just dont hook up the one that goes to the vacuum box or whatever it is called.. that's what i did about two years ago and everything still works fine

I'm still lost in the subject

I'm sensing a Pink Floyd reference there...

yea quite catchy I must say....

try this, take ur dash apart and make sure the controller for the fan **** is still attached and the arrows line up, i remember when i did the LED's in my dash i hooked that up wrong an no matter what i only had defrosters maybe urs snapped off

Already done that Kernel. I replaced the fan switch and the piece directly behind it. All the arrows line up just fine. The vacuum lines are all connected, etc.

Yes indeedy, my good friend. The problem is that my feet are comfortably numb, while the rest of me is ready to jump out of the car and run like hell. My mother told me I should get it fixed before I take a trip to the darkside of the moon.

My server was down for a time last night or I would have posted this:

An easy way to tell what part of the system may have trouble is to go to the vacuum check valve and test the lines back to the mode selector and to the vacuum canister. If you have a hand held vacuum pump, it would be pretty easy. What you want to do is remove the hoses one at a time and apply vacuum to each and see if it holds. The line to the intake manifold will have to be removed at the manifold and plugged back toward the check valve for you to test the line for leaks. You can test the check valve, too. Sometimes it cracks and is the cause of a leak.

If you find a leak on a particular hose, you will have to trace out the cause on that section.

Ok, I tried looking for the vacuum check valve, and notated the link to the picture, with the "elbow" and what-not, and there is NOTHING under the hood that even closely resembles anything that looks like that.

If it's there, I'm definitely NOT seeing it.