Ever wonder what the inside of the multifunction switch looks like? Or what may render them erratic and slow to respond?

Had some students take a look at my "bad" one this week. It was intermittent on the variable wiper settings.

Now that it is cleaned up, and bugs out OK...will put it back in and see how well it works.

 

That's interesting. Variable wipers seem to be the most common glitch. I always assumed it was in the **** on the lever - I'm curious to hear if cleaning up the contacts in the main body resolves that.