Thunder...
I recently had the exact same problem. Under light braking (dry or icy roads) my ABS worked fine. However, under hard braking (slapping the peddle down)...my light would come on and stay on until I restarted the car. All would work fine until I had to slam the brakes on again. I took it to the dealer and it was my ABS traction/anti-skid module. They replaced it and all is fine. Thank goodness for warranty....the unit was $850.00.
Good luck
