hey speed demon the blend door only changes the temp. the door that changes between defrost,floor,vent ect. is operated by vacuum.there are 2 vacuum connections one on the back of the temp control module and one behind the glove box door and of course the 3rd one is attached to the door that is being opperated.the first connection to check would be the one behind the glove box.to open up the glove box there is a cord attached to the right side dissconnect this then there are 2 cutouts in the glove box push these inward this allows the door to open more than normal.the connector is in the center it has 1/8 colored tubes make sure this is a good connection. one end of the connection is a green silicone fitting you can put a mighty-vac on this with a tapered rubber fitting and put a little vacuum on each colored tube make sure that you can hear the doors opening and closing by putting vacuum then releasing it. if the connection looked good,all doors open and close and they hold vacumme the next thing to do would be to take a look at the connection behind the temp module make sure you reconnect the fitting behind the glove box.here are the steps to get to the temp control module.
1.you need to pull off the defrost panel.it has three tabs holding it in. remove connector.
2.remove wood grain surround.this is usually takes some effort to pull this out .there are 2 9/32 behind where the defrost panel was take these out.there are 4 heavy duty tabs 2 on the bottom 2 on the top. the two on the bottom are on the left and right sides pretty much center of the oval shifter opening.the top right is 1.5 " down from top and the top left is 3" down from the top.there is a ground wire on bottom right pull this off.
3.turn key to acc position so you can put shift lever in 1st gear then turn key off.
4.to take the module out take out the 4 philips screws then pull module out of opening.disconnect the 2 wire connectors on the left side.now to take off the green silicone fitting there are 2 3/8" nusts holding it on.be very careful especially when putting nuts back on if you cross thread the studs or break one off then you will really have problems.
5.once again do the vacuum test to find where the problem is. if i remember correctly the line you want is blue but test them all there's only 4. red black white and blue. good luck. and remember to check the blend door arm to see if it is broken or even if it only has a small crack because it sounds like you have 2 problems. I usually put a tiny bit of silicone grease the light stuff to help seal a little better plus the fittings are a little snug so it helps to slide the fittings on. hope this helps -Pat