Washer won't enter rinse cycle.

My Kenmore 110 washing machine fills, agitates and spins fine. However, when it gets to the Rinse step, it does not fill and only buzzes. Adjusting the knob slightly forward does nothing. I can advance it to the next spin step and it works. I can advance it to a new cycle and it fills fine. Lid sensor is ok, water supply and drain are fine.

I cannot find any mention of drain filters (wondering if they are clogged) in the manual. Before I call someone or take apart the dial, any suggestions?