The cable to the gauge doesn't spin, easy fix or suggestion? What is common cause?

 

Probably broke in the middle, these tend to be over-looked in regular maintenance.

Pull the cable off the tire hub end and rotate tire. If the slotted end is rotating the tire hub is ok. Disconnect the other end from the speedo housing. Try turning one end of the cable and see if other end rotates. If it doesn't, you'll need to replace the cable. Not a particularly challenging task. Just be sure to note how the cable is routed up through to the guages before you remove to replace.
Ern

 

Thanks! Sounds easy to check