Dishwasher Question


I've got a GE dishwasher model number GSD1350X70 that I'm struggling with.
The short version of the problem is that during some of the cycles, the thing begins putting fresh water into the tub before it has finished draining the dirty water. The end result is that all the water gets drained out and it sits there not doing anything until the next fill cycle begins.
My understanding is that the fill cycle begins and ends based on the timer. It starts filling at time F and stops filling at some time F+T later, where F=Fill time start and T=Fill duration time.
My question is, how does the drain cycle work? Obviously it begins a drain cycle based on the timer, say at some time D into the cycle. How does the dishwasher know when to stop draining? Is it like the fill cycle in that it will stop draining at some time D+T later? Or is there some kind of feedback mechanism to tell the dishwasher that the tub is empty?
If the drain cycle works only on the timer, then it seems like there is something wrong with my timer because it begins filling the tub while it's still draining.
Any help is appreciated. Dan
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snipped-for-privacy@yahoo.com wrote:

I'm 99% certain that they just run the pump for X secs. Every one I've had, the pump always ran for awhile even after there was no water left. Or, if you cancel a fill cycle just as it starts, mine will then run the pump for a full pump out cycle time. Also, it seems very logical and cost effective to do it this way. To do it other ways adds cost, complexity, more parts to fail, etc.
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<<Or, if you cancel a fill cycle just as it starts, mine will then run the pump for a full pump out cycle time.>>
Good point here. That does seem to indicate it's a timed thing.
What do you think of my theory on the timer being broken then?
Thanks. Dan
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snipped-for-privacy@yahoo.com wrote:

What kind of timer is it? Mechanical or Electronic? I would think it far more likely for it to be a bad timer if it's mechanical. And from the symptoms you describe, the timer would be my suspicion as well.
Related issue is how old the whole thing is and how much it's worth screwing around with, buying fairly expensive parts that usually aren't returnable, etc. Also, new ones use less energy, so there is some long term savings there, etc.
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<<What kind of timer is it? Mechanical or Electronic?>>
It's a mechanical dial type timer.
<<Related issue is how old the whole thing is and how much it's worth screwing around with, buying fairly expensive parts that usually aren't returnable, etc. Also, new ones use less energy, so there is some long term savings there, etc.>>
All perfectly valid issues and in the back of my mind as well. If I can get away with fixing it for $50 or so, I'm happy. Much more than that, well...I don't know. Still trying to figure that one out. And, unfortunately, the timer looks like it runs close to $90 or so online.
Thanks. Dan
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