Dishwasher will fill,pump out, and dry but will not circulate during cleaning cycle. Is it thetkmer?
The problem can be a bad motor, a bad impeller or a bad timer. Unfortunately all of these parts are no longer available due to age of the dishwasher. Looks like it’s a time for a new one.
Here are the breakdown diagrams and Replacement parts for Whirlpool DU7400XS2 DISHWASHER | AppliancePartsPros.com
Gene.