I have the Black Box controller wired correctly to 3 different limit switches. If manually press the limit switch, the red light comes on but if I am in the middle of homing in to the zero point or jogging, it will just keep going down the axis even if I trigger the switch. Aren't the switches supposed to interrupt the motors to prevent it from breaking something? I have smashed 2 limit switches because I thought I had the zero point saved with the interface (doesn't after power down) and the limit switch did nothing to prevent the motor from advancing once it was triggered.
1) did you enable Hard Limits in Grbl Settings? See the Grbl Wiki for details Or 2) are they really wired correctly? Use the Troubleshooting Tab in CONTROL to test. In particular check that all of them respond, but also that the correct axis responds. Plugging X switch into the Z port for example, etc
