So if it keeps filling and you've installed a new pressure switch and hose, the only two other things I can think of would be the wire connection between the pressure switch and timer, or the timer itself.
1. If the wire connection is corroded or a wire is broken that will cause your issue. Try unplugging the wire connection from the timer and the pressure switch and cleaning the connections. You can use a connection cleaner to do so. See the picture for an example. Also trace the wires leading from the pressure switch to the timer to see if there is a break in any of the lines.

2. If the timer has a fused or stuck contact that can cause your issue. This would require the replacement of your timer.

Is this different from the previous pressure switch you had, or did this filling full on small load occur with both switches?
If it occurs with both the old and new switch then your problem may be a bit different. It might be a partial clog, not the the pressure hose, but in the air trap that the hose connects to on the side of the tub.

Ok so now I am going to reveal a technicians secret. LOL

Two things:
First take the hose off of the pressure switch and blow thru it to move the clog down further into the tub. Replace the hose on the switch.
Then get a gallon of good old white distilled vinegar. Pour the entire gallon into your empty washer. Turn on any cycle using hot water, setting the water level to small and watch until the tub is about 1/4 full. Push the knob in to turn it off and let that sit over night. The next morning turn it back on and let the cycle complete.
Vinegar should dissolve whatever is in there.
I recommend to my customers to run a vinegar cleansing cycle about once every 6 months. Some people will purchase Affresh cleansing tablets which work as good but are more expensive.
What happens is a build up of liquid detergent and liquid fabric softener collect in different places, dirt and grime cling to the build up and cause havoc on machines, causing a musty moldy odor as well.
Just think of what you must see in the measuring cup for detergent and softener. A thick gooey layer of yuk! Using only cold water on rinse cycle does not allow all the softener to dissolve.