A young Samurai Apprentice posted this problem in the repair forum. Sublime Master of Appliantology Stumpowitz rendered the illuminating initial diagnostic advice:
Magnetic reed switch on left side below the gray rubber bumper, shown here. Release two spring clips in front between main top and front panel using putty knife. Lift the main top and access the left and right door locks here. To access and see if the magnet is in place, remove the dispenser from lid. Gently pry the bottom of the plastic inner lid toward you then down. This will let you see if the magnet is in place on the right front corner of the innrer lid.
Which, naturally, was precisely the right prescription.
Seems to be a common problem with this washer. Apparently, the lid isn’t completely watertight and allows water to get into this switch corroding the contacts and the wires. See the attached picture of my water-damaged switch. Note the black wire disconnected.
All is revealed under the power of many good minds focused on a single problem. This is the strength of the forum. Buy your new lid lock switch here.