My '87 240 has a failure of the air mixing control. The temp selector works. None of the deflector buttons do anything. I have good vacuum going to the firewall.

It's 104 degrees here and my AC is half blowing and I can't find my Haynes manual. Can anyone give me a couple of good ideas before I get started?

Thanks

Can you hear anything happen when you push any of the three buttons immediately after the car has been shut off? If so, vacuum is making it to the switches and the problem is a hose from the switch-valve assembly to vacuum motors.
Remove the covers under the dash on each side. Remove the plastic sides of the center console. Start the engine and turn off everything except the engine. Listen carefully, you may be able to hear where the leak is. Try this with each switch pushed and "un-pushed." If not, try listening immediately after you turn the engine off. You may be able to hear it as the vacuum is lost.
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1966 122s, 1968 142s, 1969 144s, 1979 245dl, 1989 244gl

You just have to find the leak. It's usually where the hose nattaches to the manifold, but you've said you have good vacuum to the firewall.It's going to be on the interior side of the fireweall.
Just be sure to note via pictires or write down where each hose connects. It's probably going to be the supply hose where ic connects to the reservior.

Thanks. Had this happen once on an 80 GT I used to have but it's been so long I can't remember what I did to fix it. The AC is blowing out the dash vents but it is so hot I can't tell if it's cooling good or not. The air coming out the vents is around 65 sitting in park. I just felt of the drier and it is hot to the touch. I can see freon moving in the sight glass but after ten minutes of running there's no water puddle under the car. I think I may have low refridgerant. The hot drier bothers me.

No water under the car means the rubber drain is clogged.Is any of your carpet wet? Thats a sign of the drain clogged. 65 degree's at idle is not bad in 100 plus degree's. How is it when driving?