something like this happened to my car after hitting a big bump once and then once when there was a lot of ice in the wheel well. It turned out to be a wire that broke down comin off of the hub so when it happened the second time i soldered it back into the plug. Ur problem sounds more like a loose wire someplace. If i were u id start by removing the wheel and checking the wiring that goes into the hub (i believe its called a hub). Then check where they plug together and clip on. U may have bumped it when working on it.
