1997 chevy tahoe vss wire, reverse wire

My old head units volume would increase when I drove faster would that be because of the VSS wire? If so can I hook the navigation VSS wire into the one that use to connect to my old head unit?

The wire that allows the car stereo's volume to increase is that the vss wire and if so can I hook my naviagtion vss wire into it also can I hook the reverse wire some where under the dash instead of running it to the back of the truck.