2005 focus zx4, the wiper stick doesn't work either like it should or like I think it should. Pressing downward on the stalk should cause a single wipe right? For some reason, mine only moves the wipers if I hold the stalk down. If I let go at any time, the wipers stop where they are on the windshield instead of continuing back to the park position. Normal, or do I need to pull a replacement unit from the scrap yard? I've had lots of cars over the years and never experienced this odd behavior.