Extra Ground wires on Happs Trackball?

[Jakobud]

Okay, I got the 3" Highball trackball.  There are the two harnesses, one for each axis.  They have power and signal and ground on them.  But the trackball then has these two extra ground connections leading off of it.  Do I need to ground these wires?  What are they for, if there are already ground connections in the harnesses?

jakobud

[x-wing]

Those grounds are for a chassis (safety) ground.  They are not required for operation of the trackball.  What they do is help keep all the devices at the same potential so there isn't risk of a charge build-up between different devices in the cab.  If you have a PC chassis in the cab, you can run a wire from the safety grounds to the PC chassis.  Or, you can just leave them alone, they won't hurt anything just dangling loose.