For those folks who have upgraded older PS-1 F-3 (also F-7/E-6) to PS-2 there is a new sound file being posted to the MTH web site to allow the Number Board Lights to be controlled by the Ditch Lights connector and left on.
Early units used a CV board, but this did not allow full function control of lights via DCS. If you attempted to use the older sound file, ditch lights could be used, but when turned on they still flashed when the horn is used.
The request to modify the sound file has been answered and the BO and NYC files have been updated so far.
The PS-2 5v versions of these units also did not use the sound file to control Number boards. Instead a patch panel is used that tripled up the interior cab light with the 2 number boards. So even those files would not work with the earlier units.
By using the PS-1 harness you can bring 3 signals back to the Trailing Dummy A and have coupler, Reverse light, and Number Board control using Ditch 2.
For later models that had the MARS light also, that function does work too.
Hope this info helps folks who desire the full function control. G