The resistors for the light bulbs are on the main board, so plugging in a decoder will not change the way they perform except that you will be able to turn them on and off with the decoder functions.
Regardles of whether you use a decoder with the 8-pin plug or the 9-pin JST plug, you MUST remove the dummy plug that is in the 9-pin (white) socket.
They will be controlled by the decoder.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
If a locomotive is DCC Ready with the "quick plug" will its lights continue to work once a DCC decoder has been installed? Will they just be dim, not work at all, or light the same as they did under DC mode? Thanks!