[cam1]

Hi:I doubt it's in the quill. Limit switches are usually accessible (for adjustment), but hidden to stay dry and chip free.
It's not seeing the limit switch (either electrical or mechanical). Find the location of the switch, and you will most likely see the problem. If the Z is on the quill, then look into the housing that the drive for that axis is enclosed, the limit switch will most likely be located adjacent to the ballscrew. Another way to go is to have a look in the electrical enclosure, and find the switch inputs on the backplane. If you have a wiring diagram this will help alot to find the location.

regards