FWIW. This may not be the problem solver but,..... the switches are statistically the point of highest probability of failure on our older cars.
Remove the seat-shaped buttons (they pull STRAIGHT off; be careful, don't break pins underneath).
Shoot some contact/tuner cleaner (Radio Shack) thoroughly into the switches from the now exposed crevices and work the switches vigorously!
See if they work. Good luck.
If they work, you'll want to disassemble, clean and lube at some point. That's a whole 'nother ballgame!
