My parents just bought a D2 for me and I am having trouble with the windshield wipers. I can get them to go about 3/4 of the way up without any trouble at all. at that point they stop and if I leave them on they figit every 2 minutes or so. If I turn them off I can push them down after about a minute or so. I have already tightened them to see if that was it but hasn't worked. Any Ideas?