how to fit it?

i have a 5kg commodore hoover washing mechine it has on the nob super wash, wash, rinse and spin dry... thats the cycle but when the nob in in at either super wash or wash all it does is fill the washing mechine with water, and the nob doesnt tick like it use to but if i turn it to rinse it finishes the cycle itself... and works it just doesnt wash can anyone help me