Bosch diswasher It takes almost 4 hours to run through a full cycle. It seems to stay in the rinse/dry for too long.

Not sure but it could be that the washer thiks it needs water (i.e. the water us syphoning out as it is coming into the dw. I hav a fairly new Sears Kenmore and the problem was that the drain hose not eleveated enough. My fw is on main floor and drain hose goes down thru the floor into the basement. What was happening was that when the 1st drain occurred "gravity" caused the new water to continue to syphon and it would stay in a cycle for a long time. I corrected by re-running my drain hose to the the drin below the kitchen sink. That drain is elevated above the floor enough so gravity does not take over. Hope this helps.

Check heater element for open circuit, if the dishwasher fills and empties and wooshes the water round, there is little else to go wrong