So my dishwasher will fill, and start washing, but then the start/cancel light and washing light start flashing and the machine stops.

In diagnostic mode, I get code 6-4: Inlet water - Float Switch Open. I have replaced the control board based on the recommendation of a local repair tech who came out twice - no change.

Replacing the control board seems to eliminate the "open fuse to fill valve and other triac loads," and "fill valve triac on control shorted" faults.

After the machine fills and then stops the cycle, I hit "cancel/drain" and it pumps out and doesn't backflow into the machine so I don't think the drain check valve has failed.

It stops filling when I open the door so I don't think the fill valve is stuck open.

This seems to leave the most likely cause as the overfill switch stuck in the overfill position. I take it the overfill float switch is in the front right of the bottom of the tub, round hat looking thing? I can hear it click when I raise and lower it but can't be certain that it is working properly.

I plan to get out my multimeter and verify it is opening and closing and go from there.

What else should I look at?

Thanks,

Mike