My Arison margherita 2000 wd won't stop filling, any ideas?

The washer starts is cycle as normal but doesn't stop filling. I've taken the top off and had a look - no burnt out contacts. On the left hand side towards the back there are 6 plugs, green white and red. If I pull out one of the red plugs the water stops but I've followed the wire through the machine and found no obvious problems. If I put the contact back in the water starts running again. I'm stumped. Any ideas?