Are you able to jog the axis? Press the ''hand'' key to toggle through the jog speeds, maybe set for ''jog rapid'', then press +X and see what happens.
In order to run the spindle you may have to set a spindle speed first, I didn't go through all of the manual and it's been a long time since I've had my hands on one of these.
The loose cable might be for the coolant pump or something judging from the connection on the other end of it.