I've been having a problem with my vantage vue with the wind direction not changing for the last several weeks.
I finally went and took it down and tore it apart to see what was going on.
The vantage vue has a magnetic sensor with a counter weight on it inside the unit. In my case, that counter weight and magnet assembly had broken off inside the unit.
My theory is that here in the desert we get these dust devils that can be pretty strong at times and I think one of them (or many) must have hit the unit and caused the wind vane to spin rapidly and wildly back and forth, breaking the way the counterweight and sensor was held to the top of the rotating shaft.
I simply used a little JB Weld and made sure to align it properly.
I did see the sticky on sending units in to get refurbed, but this seemed like a quick and easy way to fix it.
Just posting this because I had done a bunch of searching on it, but hadn't seen anyone really address what my issue was.
Here's an image of the part in question.