I've got a Megane 175 and where I would expect the door puddle lights to be, there's just a crappy plastic blank. I've pulled it out and had a look behind but couldn't see any wiring or anything (not had the door card off). Is is likely the wiring is already there, or not?
I would imagine it's probably just dropped down, I can't see Renault making a separate wiring loom for each Megane. Have you tried removing the top quarter of the panel, and have a look down? without taking the whole door card out?