dcc lights

This is really to act as a guide if you wish to use your favourite 21 pin decoder in some of the later RTR releases. The Dapol O scale 08 being such an example. It is a slight variation of my reply in the Dapol 08 thread but may become relevant as further O scale RTR locos are released...

I wonder if any luminary out there can advise me on this - Looking at a chip I have just put into a modified Heljan 37 (Loksound XL v4.0), it occurred to me that I might be able to wire the red lights to spare aux ports (an extra one now the fan is disconnected for good) and programme them to...