If you don't have rear lights, the yellow wire won't go anywhere.
Isn't the AO for Athearn? Why not use the correct decoders for the locos you're installing them in?
Rotor
Jake: How often does the train go by? Elwood: So often you won't even notice ...
Below is a picture of the original circuit board for the MRC F7A diesel locomotive. I am replacing it with a Digitrax DH165AO DCC board. There is a yellow wire that comes from the locomotive and I know that yellow is usually for the tail lights which this locomotive does not have. Where will the yellow wire go on the DH165AO since it's not light related? I assume that the blue and white wires are for the headlights.