I have two NPN NC bullet type proximity switches on my X Axis. Normally the inbuilt LED lights up when the target metal approaches and triggers the switch. As of last week, one of the proximity switches is lit the whole time, I cant change its state. Mach is reporting the error when I try to home the X axis. I've run a new switch to the same connectors as the faulty one and the new switch stays lit also. Note, in case it matters both switches were in parallel during this test. I can't spot any obviously loose wires in the control box. Before I start to tear into the control box, has anyone experienced this type of failure mode from the proximity switch before? Cheers. Tony.