I should understand this by now, but I've had trouble figuring out the difference between the different modes. Even on test drives, the salesmen tend to hedge their explanations. Can anyone explain this clearly and when it's best to use which. Also, I was on a test drive tonight and asked to use the windshield wiper spray. And it basically dribbled out but never got the windshield wet. The only water that came out ran outside the field of vision. Is that customary for the Clarity. The salesman didn't have a good answer for that either.