kev20v

help !!!!!!!
im having trouble with he drivers door lock on the wifes car , when its freezing .
the door doesnt get locked , it opens ok then seems to freeze the catch in the open position so the door wont shut again ,this also happens in reverse sometimes ie; the door wont open !
it really getting on top off us now and need it sorting .
.........it only happens when it freezing weather ........

any advise would be appreciated , cheers kev
its a 1998 cordoba 1.4