I have a 2002 3dr st170 and it has an issue with the drivers door central locking.
Best way to describe the problem is to put the different ways of locking/unlocking and what happens so here goes.

If i push lock on the keyfob passenger locks fine but drivers door does nothing so naturally the passenger door unlocks again.

if doors are locked and i push unlock on keyfob passeneger unlocks but drivers stay locked.

if i use key in drivers door all doors lock and unlock as normal.

if i use key in passeneger door then it does what it does with keyfob.

so basically the drivers door wont work with the central locking but the central locking will work with the drivers door.

Iv been told that it could be the selonoid in that door but dont know how to check this. Much help appreciated.