After looking through the wiring/pin layouts for a 2002 X-type and 2004 X-type, it seems that I should quite easily be able to add the puddle light/courtesy lights into my 2004 X-type. It seems the pin that was used is unused now in the 2004 x-types. Anyone know more about this?

 

Note that the pin on the GEM is an earth/ground point, switched to earth by the GEM itself as required. Power to the puddle lights comes directly from the Battery Saver Relay. Before starting, put a meter on the GEM pin to check it switches to earth/ground when it should for the puddle lights. Also, give some thought as to how you're going to run the wire from the cabin to the door interior. Not necessarily as easy as you think! Depending on your exact model, there can be spare wires in the cabin-to-door harness, eg on Memory Seat/Mirror cars, the wires for powerfold mirrors are fitted but redundant and could be used. Others who have retrofitted puddle lights have just wired them in to a standard earth/ground and powered them from the footwell light supply.