To switch on the Blue Pullman's cab lights from the box use F2. If like me you are using the Gaugemaster Prodigy, F2 is non latching so you have to keep your finger on the button to keep the lights on, which means you can't do anything else !. So i've worked out how to reassign the cab lights to F4. Then I decided wouldn't it be nice if I could control each end's cab lights independently.

So here's how to do it:

On both both power cars re program CV 36 from 4 to 0 (this disables F2 activating cab lights)

On your programming track one car at a time:

Set CV 38 on one power car from 0 to 4 (this sets F4 activating cab light)

Set CV 40 on the other power car from 0 to 4 (this sets F6 activating cab light)

Put them back on the main track and F4 and F6 will operate cab lights individually - tadah.

Full technical referance manual for decoder is at:

http://www.soundtraxx.com/manuals/MC1%20Tech%20Reference.pdf

Have you noticed Olivias trains are selling the decoders seperately for £13 - bargain for a 4 function 21 pin decoder