Well, removed the airbag exposing the 2 horn contacts. Pressing either button made the horn blow. The contacts are actuated by a pair of bumps on the back of the airbag that rest over the horn contacts. They are fixed to the frame of the airbag and do not move in or out when the airbag cover is pressed. I presume the entire air bag moves when the cover is pressed to close the switch contacts. I cleaned the contacts with a bit of emery cloth followed by contact cleaner. It does take a fair bit of pressure, but the horn is working.
In the second pic the airbag is rotated 90 degrees; the right side is actually the top of the airbag. Those cone shaped bumps are what presses on the contacts