Help needed with 3040 chinese cnc mill limit switches

I have recently changed the contoller board on my mini mill to a GRBL 1.1h

It has installed successfully and happily doing what its supposed to be doing.
In my electronic naivety I assumed that the x/y/z limit switch pins would operate when shorted out, but this dosen’t happen. I have the Limit switches wired common and normally closed. Using a continuity tester across the c n/c terminals with the switch lever in the rest position results in no reading (as would be expected) then close the switch lever and continuity is there. But when either the x or travel is set in motion and the limit switch lever closed, nothing happens the axis continue to travel.
Am I missing something?

Enable hard limits with $21=1. (Disable with $21=0.)


Thank you mate. After your pointer I have now found those settings in the UGS setup wizard.Thank you again.


@DuncanC That’s why we are here. I’m glad you were able to sort it out.