If you find theres no blockage at the pump or pump filter.Theres a white plastic ball at the other end of that drain pipe just under the drum if you remove the clip retaining it you will find that theres debris caught between the ball and tube , thus causing flow interruption during rinse or drain cycle , this causes the light to come on.I eventually discovered this for myself , may be helpful to others.
john sheehan
March 2010