Class 56 Lights (56109 Load Haul)

[Malcolm-801628]

A few years ago I put a Hornby 8 pin decoder into 56109. It already had directional lights fitted (whether this was factory or old owner I have no idea, but I assume Factory fitted seeing there is a holder on the frame to keep the bulb in place)

I can't remember exactly what I did and was a newbie to the hobby then, but the situation now is that the light bulb's are wired directly into the Decoder socket.

Not sure if there were any resistors or anything in there before. But light seem a bit too bright. So much so that the tail lamps and the headlamps light at the same time because I guess the light is so bright the red bar picks it up (See inside body image) 

So my question is, what do I do to stop the red lights showing with the White (dim it somehow) and how do I get the Red only to come on ?