it could be that the wires on your switch are loose and/or disconnected.
1) Remove upper and lower plastic covers on steering column
2) Remove 2 or 3 phillips screws from the backside of the wiper switch assembly. They are tiny screws and will take a small screwdriver to fit in there
3) at this point the wiper switch should be 'loose' in there but you won't be able to pull it out probably. I had to trace the bundle of wires from the steering column back under the dash. I wasn't able to unplug it (not sure if it even does) but I snipped the plastic tiedown and that gave me enough slack
4) I believe I was able to look under the steering wheel towards the switch and I could see one little wire loose from the wire bundle. I soldered a few inches of wire onto it to extend it. I did that because there's no room in the steering column to solder the broken off wire back onto the board.
5) Now you need to grab the wiper switch and wiggle the circuit board out of the steering assembly. It was difficult to get mine out but it eventually came loose. It won't come out far because of the remaining connected wires. You should see one point on the board where a wire had been soldered but has broken off
6) Feed your extension wire up through the switch assembly and solder it onto that point. Give it a test and hopefully it works!
Hope that works. You should join www.mr2oc.com if you haven't already. It seriously only took about half a minute to find a possible solution to your problem.