Tried my wife's radrunner+ display on a radrunner 2 and no lights now

[mushroom]

So my secondhand radrunner 2 came with the basic power button on the handlebars.
My wife has a redundant Display and power button because of her eggrider V2.0
I tried swapping them over and everything works except the lights.
The front light on the radrunner 2 has a switch on it and the radrunner+ doesn't but that's the only difference I can see, they both have the same plug

Any ideas ?
Do I need a radrunner+ front light ?