The answer to your question is yes
. I would start at the switch. I would assume that you have air there, and I don't see any reason why you wouldn't. Then I would check the lines running to it, if you can. Make sure there isn't kinks or anything (again, I doubt that there would be).
Then move on, and check your wiper motor (or was it engine
). See if you have air there (again, my guess is that you will). After you check that, then I would see if you can figure out if the motor is frozen. If it is, see if you can take it out and disassemble it. We had re built ours before, and it usually helped some (now we are all electric).
Maybe somebody else that has more knowledge about the air wipers will chime in.