I click on the Icon to start the homing cycle, and my machine immediately drives up past my Z limit switch and begins trying to move past its capabilities/clicking and wracking. My limit switch works when I drive it manually, and I have my Hard limit switches enabled. I am not sure what I am doing incorrectly. Any advice?
Test your switches in the Troubleshooting tab - likely something like X switch plugged into Z port (will still work for Hard limit - but Homing needs the correct switch on the correct axis too)
If the Troubleshooting tab detects it, Grbl will too. Unless you carriage cannot reach the switch lever but your hand could Check the wires, or checked the results in the Troubleshooting tab?
I had this happen to me this week and I figured it out. I think what happened is the thin metal arm on my Z limit switch wore out causing the machine to hit its actual mechanical limit before it would trip the switch. When mounting the new switch, I also discovered that you need to make sure the switch is positioned so that it will trip before it hits its hard mechanical limit. Probably common sense but worth throwing out there for folks that are reading this. Getting it positioned just right will also ensure you give your machine the most out of its Z height. My machine is a LEAD1010 but the same rules apply to others.