At zero position the tab moves across and pushes this switch open. When the stepper increments the switch MUST close.. if it doesn't then the machine will continue to "search" for this closure.
So.. at ONE step on the stepper this switch must read closed with a DMM ..NOT SIGHT.. use your DMM.
Just a little tip.. if the switches are working, there is no need to adjust them. You are asking for trouble doing this.. and it looks like trouble you got.
Aint broke.. don't go fixing
