I had 2 Maytags do exactly this twice.
The first time some stepped on the top of the lid and deformed it
slightly so that the plunger wouldn't activate the lid switch. As above
these will fill with the lid switch open. Activating the lid switch
with a piece of rod started the agitation. Repaired the deformed lid.
The second one the switch just went bad. (Micro type as I remember).
Jumpered the leads and the washer worked until I installed a
replacement.