Glowing brake light?

[Fulcrum525]

(Note: Not the parking brake light but the one next to it, the pad sensor indicator)

Started back in the winter. The parking lot I was using daily was never plowed so I often had to park on very uneven ground. Sometimes when I started the car the light would be on and when driving away I would feel the light 'jitter' and the light would go out.

Now i'm driving 100 highway miles every day and the light occasionally glows (It doesn't turn completely on) What's more it really likes to do this when i'm on a banking right hand turn and turns off completely if i'm taking a left hand banking turn. (Only at highway speeds) The light also goes out completely when I apply the brake pedal. It will also occasionally do this on straight sections.

I'm at 290,000 miles and have never touched the calipers. The front brake pads still have plenty of meat on them adn the rears are less then a year old. Potential note-the right front wheel always has considerably more brake dust on it then the left side.

What am I looking at? Bad sensor? Bad connection? Or potentially a seizing caliper?