Yes you do have a problem.
Best thing is start hitting the PNP`s for another 240D, and remove the parts.
Left and right control are for the water valve. they connect to a cable.
The center one is for the Blower Motor.
The plastic piece they attach to is fragile, and is riveted to the Heat/AC box.
maybe with a battery operated Dremmel you could grind off the rivet heads.
The knobs just pull off, the nut behind I think is a 22mm or use some needle nose Vice Grips to loosen them.
The face Plate then gently comes off the 3 threaded pieces.
The Switches as I remember you have to slide the to the right or left out of the slots, and they drop back and out of the Fragile piece that is Rivited on.
The right and left switch, rotate the center and the cable will move out to unclip it.
You do have the best type of heater/ac controls, I have a 240D heat/ac box to install in my 85 300D to get rid of the push button controls. repair what you have.
daw-two in his thread he is swapping in a manual CC box.
http://www.peachparts.com/shopforum/diesel-discussion/319593-1984-300d-light-ivory-unique-car.html
Was the car this way when you got it?
Where is Woodacre? Socal?
Hope this helps.
Charlie