If you use power to get the motor to run it is usually one of the switches. You can jump them out with some wire to find when they aren't working or use a meter to test for continuity.
Good find, way cheaper than a service call or a new unit .
On a side note we got our dishwasher when one of my daughters asked about the "new" looking dishwasher un one of her friends garage. The mom said yes it is brand new but it leaks. Oh, she told them, my dad can fix that. The mom told her have him come and get it out of our garage . They had already bought another new one after two warranty calls and it still leaked. I ordered a couple gaskets off amazon and put them in. You could see where it was leaking on the side. Not any more, and it is a nice LG with a stainless front.
