My bet is on the brushes being worn out. THat's what mine started to do. I left it too long before addressing and when I finally did ($10 part from Autozone), the commutator rings were wore out of round. New brush set lasted about one month, then light came on steady. One of teh new brushes has broke the wire attached. Poor little brush must have been bouncing like crazy. Chage the cheap brush holer ASAP and save the commutator rings.
