Screwdrivers: Mini-screwdriver set; medium flat blade;
12" Phillips #2; Torx T-27; Torx T-20.
10 mm extra deep socket.
Box wrench to remove ground strap on battery (13 mm on my car).
Remove the battery ground strap. Remove the two screws under the hood over the instrument cluster with the Phillips screwdriver. Remove the two screws (T-27) on either side under the steering column. Remove the metal panel under the steering column. Remove the two screws on either side of the steering column exposed after removal of the lower panel. (Missing on my car after two expensive AC repairs by a dealer -- loose ground & inoperative clutch field and pulley.) Pull out the oval dash panel running from the light switch on the left past the EATC head on the right, working around from the bottom. It is held in place by several plastic snaps. There is no need to completely remove the oval panel. Pull it out just far enough to remove the head unit.
Remove the four screws (T-20) holding the head unit in place. Pull it out. Use the 10 mm extra deep socket to remove the nuts on the upper connector on the back, and remove the upper connector. Unsnap the two lower connectors. Remove the head unit and take it to your workbench.
Make a drawing of the unit and write the names of the six lower buttons on your sketch. Otherwise, you may forget the correct arrangement.
With a medium screwdriver, gently lift the four snaps that hold the front panel to the head unit. There is no need to remove the front panel completely. With the unit upside down, pull apart the layers of circuit boards. You will see that the buttons along the bottom are part of an assembly that is held in place with six plastic welds. Use a sharp pocket knife to cut off the six plastic welds. It helps to sharpen the knife after cutting each weld. Push the buttons from the outside to remove the button assembly.
Note how the buttons fit on the assembly. Gently remove the buttons from the flexible backer and the thin rubber grommet. Mix a small amount of clear, two-part epoxy. I used 15-minute epoxy purchased at Home Depot. Using the tiniest screwdriver from a mini-screwdriver set, daub a small amount of epoxy into the recessed center of each button. Spread it in a very thin layer. Keep epoxy off of the reinforced ends and the sides. Let dry for 24 hours. After the epoxy dries, scrape off any excess with a small screwdriver.
Reassemble. There is no need to glue the button assembly in place. Test by pushing the buttons. If you feel and hear a click upon pushing each button, you have done the job correctly. If a button is "frozen", it either contains too much epoxy or is not fully seated. You may be able to scrape down excessive epoxy with a small screwdriver. If that doesn't work, simply pry out the epoxy with a small screwdriver and do the job over. If you happen to break a connection on the flexible backing, it may be glued with epoxy. (I broke and glued two.) If you break the rubber grommet, there should be no need to glue it together if it stays in place. (Mine broke in one place.)
Replace in the car and test.