I have a 2005 Chevy Impala. The windshield wipers work and everything, but when I turn them off, they go to the up position instead of down, and when I manually put them down, they go back up.
The wiper motor has a switch which sets where it parks the wipers by cutting the power. For some reason the switch is not being operated at the right part of the cycle, if you examine it then you should be able to see why. Be careful to keep your fingers out of it if you're running it to check because wiper motors are very strong.
The wipers on my 02 Venture van same thing, for two years, and I've tried everything. just learned to live with it.