ge front loader won't enter diagnostic test mode

It sometimes wasn’t spinning, except in drain & spin cycle. On searching for answers, I found reference to diagnostic/test mode. I tried the sequence for this (power button, unplug, plug in, signal, delay start, signal, delay start) and nothing happened. It does mention that a failed water level switch can cause it to not enter test mode. This might be consistent with other symptoms, such as getting ‘stuck’ at some parts of cycle – it drains, spins, and goes back to earlier part, repeating several times, but usually eventually continuing on.

I cannot find a reference to a water level switch (as mentioned above) in the parts diagrams. Is it something I can replace, and where is it?

If it will not go into diagnostic mode that suggests the control unit is the problem. It is an expensive part but if you want to try replacing it and you buy from this site you can return it if that is not the problem.