If you can't find a way to adjust it, do what others that have non-adjustable sensors do to trick it: they add an air chamber to reduce the air pressure. Think a tee-fitting, tubing, and a 1/2 liter container for starters. good luck. The switches work off of air pressure, so adding volume to the hose reduces the air pressure increase as water level rises.

I have found several youtube videos about this and this one might be helpful. If not, there are tons of them to help. This is what someone said, it is the screw on top but if you have six screws, still don't know which one it is. I hope you find out.

Here is a link that might be useful: Adjusting water level on front load washer