Have a z-axis servo alarm that I need help troubleshooting. I have gone through the steps in the manual to try to figure this out but want another opinion before I break down and call in the troops!

1. Checked the plugs at the motor in question, and they appear free of coolant and chips (as clean as can be expected for a 12 yr old machine).
2. When power is disconnected from servo motor and machine is booted up, no alarms are present.
3. Tried swapping the wires at the control box (servo control) with those from the x-axis, and the alarms pop up for the x-axis now.
4. Checked continuity through all 4 wires of the cable with both ends disconnected from servo controller, and servo motor. Good contact.
5. Checked ohm reading across motor pins (ground to leg, leg to leg). No ohms ground to leg, about 1.5 leg to leg.

Is it a motor, drive, or cable problem (or something else)?

Thanks!