I have an HO S4 diesel.  It came programmed that both lights stay on regardless of the direction of the loco.  The light in the direction of movement is brighter than the opposite light (rule 17?).  I have tried everything I could find to change it to a directional light (light only on in the direction the loco is moving).  Some threads said CV 49 and 50 and some CV 33.  Nothing changed anything.  Is there a data sheet available showing the correct CV and what it should be set to to get desired lighting effects?