Hello,
I am new here, first time posting.

I got a rather difficult problem to solve. We have this old dishwasher which has started overflowing to the floor. The problem happens only sometimes. Most of the time, the dishwasher works fine, no issues.

I have read other threads here and out on the internet, for example this one:
http://forum.appliancepartspros...lowing-out-bottom-2.html

I have checked the float and the float switch, they are both fine. Float moves freely up and down. The float switch functions properly, I checked it using a multimeter.

The inlet valve seems to work properly, because the dishwasher stops filling when it needs to (most of the time).

What could I check next?
Does it have a control board which needs to be replaced?

Here is an interesting thing I found (may help in troubleshooting):

The dishwasher stops taking in more water (filling up) BEFORE the float switch cuts in. I wonder how does it detect that the water level is enough?
Is there a second float switch somewhere?
Or is this a "timed fill" system, meaning it opens the inlet valve for , say 1 minute and then stops.

The only people that help here are volunteers and other customers/members. The people that own it don't seem to have much interest in it or answering questions here.

I only help with stuff I am familiar with or if I think I can give useful advice.

You are right, the water fill is timed. If the water pressure is high and water comes in too fast, filling the machine too full, the float switch should stop it from overfilling. Or if it fails to drain all the way and starts filling again, the float switch will cut off the power to the valve.

Since yours is intermittent, I'm wondering if it might be the way you are loading dishwasher or maybe its something in the dishwasher splashing water at the door seal.

Some of the Things I've seen in customers homes are large objects that splashed the water right at the door seal. Like cookie sheets and other flat objects.

It could be a spray are with a split in it and I've seen housings under the spray arms leak too, forcing water towards the lower door seal.

How much water is it leaking? Is your door seal soft or hard? Is the water coming over the tub or just accumulating under the door area?