Curious,
When were your trucks built?
Mine was manufactured in March 2006, and I don't seem to have this problem in any setting, although when I use the Washer setting on the rear, sometimes the wiper will begin upwardsw after it is supposed to stop. It gets stuck just a bit up from the bottom. Not s real iisue, as I just run the wiper for one cyle in 1 and it corrects itself back to the down stopped position.