The Haynes manual for the TD4, shows all connections to be plugs / sockets, so no wiring needs to be altered / soldered. Is the L series wired differently...?
Once you have tasted flight you will walk the earth with your eyes turned skywards, for there you have been and there you will long to return. - Leonardo Da Vinci
it doesn't mater you can do it either way, here is how I did mine
unscrew the top of the shifter and it is easy to remove the warning ring, the trier and the spring,
take of the screw and the switch comes of easy, this time instead of loosing time rewiring the plug I've just eliminated it and welded a electrical wire from a brocken home aplliance for extra protection
put it all back on the shifter and redoo the wiering with an electrical connector