Just a thought, but I had the switch thingy for the brake lights stop working (in the panel under the steering wheel - at the top of the brake pedal).
When I bought another one and replaced it, the brake lights started working but the cruise stopped working (I had to take out the cruise switch to be able to put in the lights one). It turns out that I didn't screw it in enough. They're in a very awkward spot, but is it possible that yours has simply lost contact, and may just need to be screwed in that little bit more??
Hopefully it's something as simple as that.
Good Luck.