This thread doesn't have a final success answer, so I thought I'd post how I had exactly the same issue with the red and white lights at both ends coming on at the same time.
The problem turned out to be in one of the electrical couplers, each coupler is a socket that contains two metal contact plates inside. In mine, one of the coupler sockets had the metal contact plates converging and actually touched each other at the open end of the socket thereby causing all lights to be on no matter the direction. Simply putting a flat screwdriver in the socket and pushing each plate over so they sat in their respective halves of the socket fixed it, I think it even clicked into place.
Hope this helps, I created an account here just to post that answer since having the same fault in my brand new model drove me mad too.
Andrew
