I performed this upgrade myself on my GLX, which came standard with electric cloth seats and non puddle lit doors. The donor car was an SE model, with the half leather seats and illuminated leather door cards, which I swapped into mine. The wiring (as with most 406's) was present in the door, so I plugged them in and activated the sill illumination in PP2000. To my surprise, they started working! Many people had reported that retrofitting illuminated door cards to a non illuminated car didn't work, even once activated in PP2000. However, all these reports were from full-mux cars, and mine is a semi-mux car.
So for those upgrading, if you have a full-mux car, they probably won't work without wiring modification to the door, even if the connector is present. However if you have a semi-mux car, they should work when activated.
Thought this might help someone
Benjamin