Water fills the bottom of the unit but doesn’t spray.
We have tested the float switch, the water hose, and the water inlet valve (which we replaced).
Whirlpool WDF750SAYW1
First thing to check would be if there’s power to the wash motor.
Depending on the installation, it’s sometimes easier to bring the dishwasher forward and test directly at the motor, or remove the door panel and check at the motor connector on the PCB.
In any case, if there’s a 120V tension there, the dishwasher tries to clean and it’s very likely that the wash motor is bad.
For your model, it seems the wash motor is no longer available by itself so you have to replace the complete sump assembly (WPW10482502)
If there never is 120V at the motor, you’ll have to figure out why. Does it think the door is open? Stuck key? Bad PCB?
It’s very often the wash motor for this model and your symptoms.
I think this is the same problem I am having with my WDT720 - before attempting to change the pump motor, I want to be sure.
I put a couple of containers upright on each rack and ran a cycle, everything sounds normal but there was no water in the containers.
Seems pretty definitive to me, just want to check with experts before throwing money at it, It is only a couple of years old, I run it once a week or less, but it worked perfectly last time - just over a week ago.