whirlpool awm 6120/3 is not automatically clicking through the cycle?

The appliance is sticking after the wash cycle and the start/pause button flashes and the span indicator moves to 0. I can manually turn it off, move it to the rinse cycle and then it does the same and won't automatically go to the spin cycle. But the spin cycle works if I programme it directly to the spin cycle. So each function seems to be working individually, but appliance won't work through from wash to spin automatically. Any ideas what's gone wrong here? Is it easy to fix?