I have a 99 Sierra Z71. The wiper blades have somehow how started stopping about 1" above the dot that is positioned on the windshield to designatethe correct location. I thought I could remove/replace them on the spline to reposition. I have removed the nut that appears to hold the blade on a spline. The problem is they won't come off, not even after I took a pry bar and tried to lift. The hood has to be up to remove the nut so you can't lift the wiper blde to the vertical position. Anyone know why the blades won't come off with the nut removed or know another way to adjust the location of the blades?