Rod,
When I looked up the diagram for the DZ-1000 and AUI, it is exactly how I have always wired my switches, but when I looked at the diagram that shows the wiring diagram form the DZ-1000 non-derailing function it shows the ground wire that goes from the AIU "IN" to the terminal block "Common" also is wired to the outside rail of the track. I do not have this wired up.
Darren