[CharlieSummers]

Model MDBD850AWW, ran fine until last evening when the wife complained about a, "funny noise." Appears that the pump keeps running after the water is gone. I removed down to the Rinse Arm Assembly, and found and removed much cruft (torn plastic, twist-tie, etc.) from lower wash arm and beneath.

Am reluctant to remove farther until asking the pros here...my current assumption is that whatever switch shuts the pump down once the water is gone is blocked by another strip of plastic junk, but then I've been all wet before.

Would greatly appreciate any advice and suggestions.

[denman]

Here are your parts includes a wiring diagram
Replacement parts for MAYTAG MDBD850AWW Dishwasher - Undercounter | AppliancePartsPros.com

As you can see on the wiring diagral there is not a water sense switch/device.
Sounds like your control board may be shot.

Try removing power from the unit for 10 minutes or so to see of it will reset.