I had that same issue on my '99. Would be a beautyfull day, not a cloud around and they wipers would cycle once for no reason at all. :huh: I agree, your MFS is bad, and just cleaning it may not work for long, time for a new one.
3rd the MFS. It includes the hazard switch when you remove it so you won't be surprised. You have to remove the cover over the steering column. Once that is off, it's one connector and a few screws if I remember correctly. I was cheap and got one from a junkyard. Been working ever since.