Dawn good luck waitiung for replies on this forum. I never got one, Meanwhile, I think I had a similar problem, and it sounds like insufficient water is getting to your tub. When dishes don't get clean its often a problem of insufficient water getting to the tub. You are correct to look to the water intake valve and solenoid and also to check the screen in the valve for blockage.

You don't access these intake parts via the tub and the bottom sprayer. Instead, you usually go into the bottom, smaller panel right under the main door after removing the front plate, and look for a water line, usually either flexible copper tubing or a silver reinforced flex line, depending on who installed...its usually on the front left. Attached to it is the water intake valve...the water line goes up to a metal plate that attaches to the DW frame, which you will need to remove (the screws), and then the intake valve is actually two parts of plastic--a black terminal with two leads, and the plastic valve itself.

If you have a terminal tester, you can test the part before taking it off by removing the leads and putting the tester on the terminal to test for continuity. You'll have to read those details elsewhere. Also, there are 4 screws that attach the plastic valve to the metal plate---if they aren't fully rusted and you can get them off, you might try looking in there first to make sure the screen is not completely plugged---since you are reporting sand everywhere, maybe this is the only problem a plugged screen.

If you have to clear the screen, after you do so its worth trying to run it first before replacing any other parts. If that doesn't work bring the valve to a local parts/repair place and they probably will test it for you if you can't, and they will have a replacement for about $20 -25. Its not that hard to take out and put back in.

Good luck!!

JoeK