Press manual, then press and hold power then press and hold start. If the servos stay active and you can jog it, go into the back cabinet, find the two long terminal blocks half way up on the left side. One of the two will have a series of wires and jumpers between terminals 37 to 42.
The side that has all wires is the side you are interested in. The wire from 37 goes to the X-limit switch, 38 is the return. 39 to the Y switch, 40 return. 41 to the Z switch, 42 return.
If you have a bad switch, you can find out which it is by linking the matching pairs. Start with a prove-out between 37 and 42. If that works, try linking each switch individually (37-38, 39-40, 41-42). There is a possibilty that you may have more than one faulty. These are only emergency overtravel limits and fail because the switches never get actuated so they corrode up. Trace the bad 'un, replace it or leave the link in.
Go for it!