If the washer won't stop filling, even when you turn it off or unplug
it, then the proplem is in the fill valve.
If the above doesn't cover your problem, then the fill level is
controlled by two components: the pressure switch or the tub that
connects it to the tub. Here are the possible options:
1. Problem with the switch itself. Remove the tube and blow into it.
If you hear a click, it probably isn't the culprit.
2. Tube has a cut in it, or has come off at the switch.
3. The nipple where it connects to the tub is blocked by debris. This
last option is more rare than the others, and might possibly require
removal of the basket to clear out the debris.