I've got a GE dishwasher model number GSD1350X70 that's having
"issues."

I noticed that during the drain cycle, the water pouring out into the
disposal was at a very low pressure and the dishwasher would begin
filling up before it had completly drained. So, I thought fine,
something wrong with the drain mechanism. Took it apart and noticed
that the flapper in the check valve assembly was all mangled. Got a
new check valve assembly and now it's draining like a champ.

However, I still have the same problem!

So it appears I have more than one problem. Only now, on some of the
cycles it will drain before filling up again and on others it won't.
It'll keep on draining while letting fresh water in at the same time.

I thought that maybe the fill valve solenoid was bad, but putting an
ohm meter to it shows some resistance (maybe a little less than 1K, I
forget) and it does seem to turn the water flow on and off.

I then went through the exercise of measuring the water level in the
tub at the end of each fill cycle. It varied from about 2 cm on the
low side to 6+cm on the high side! Seems like quite a range to me.
And, when it has 6 cm of water in the tub, it can't drain it fast
enough before the fill cycle begins again.

My next guess at what the problem could be is that the timer is bad but
I would like to get some input before I invest $50 to $100 on a new one
of those.

Any wisdom is appreciated.
Dan