If I'm not mistaken, this looks like a KDS-20. I don't know if the KDS-20 uses the same drain valve as the KDS-18, but on my 18, you can really hear the snap of the drain valve when it opens and closes. Do you remember hearing a snapping sound when your dishwasher was working and draining properly, and if so, is it still snapping like that now? If it did, and it is not now, check for a broken wire at the valve, and if the wiring is okay, check to see that the timer is sending power down to the valve.
If the dishwasher is only partially draining, are you able to empty it completely by starting a cycle, then immediately pushing the Cancel/Drain button? (Might take a couple of tries to completely empty.) If so, this indicates a blockage somewhere in the drain line, or if the line is clear, the drain impeller itself might be partially broken.