Hi. When I try to switch from highbeam to lowbeam, or vice versa, the lever periodically does nothing.

In a bit more exciting event, it recently went from high beam to no headlights at all, came back after I furiously flipped it a few times.

While I can ususally get the desired effect after a few trys, wanted to know:

1) What is the likely cause of the problem
2) How easy is it to fix, and if not easy, how expensive?

I changed the bulbs for sylvania super-premium halogen (the blue-white ones) about a year ago, since it is hard to see in lowbeams at night. Helped a bit, but I hope did not cause this problem...

Any advice welcomed!

Thanks