[craiginsd]

The upper spray arm on this unit receives water only intermittently... much less of the wash cycle than I would expect. I'm not sure whether it's supposed to only get water pumped through it occasionally, but I'm seeing that the dishes and glasses on the upper rack are not being cleaned effectively. I have determined that there is no clogging in the tube that feeds the upper spray arm (by hooking a vacuum up to one side of the tube), but the pump assembly does have a sticky drain solenoid, due to rusting of its shaft. I'm not sure whether the drain solenoid also operates a diverter valve that sends water to the upper sprayer, but it seems these problems might be correlated. If not, I do not know where else to start looking for a problem with the upper sprayer. It might be worth noting that the dishwasher has no problem draining... there is never standing water at the end of the wash cycle. I would like to get assistance on what else I can diagnose to be sure that I order the right parts the first time.
Thanks very much (in advance)!
Craig