Electric door locking

Hi all,

My occy has developed an intermmittent problem with the driver door electric lock - sometimes it does not work! this is the case when using either keyfob, internal switch or the key.

I took it to a local garage who replaced the lock actuator - still no luck so they tried replacing the window winder (which apparently has the locking ECU onthe back) still not working but now it is not intermittent it does not work at all. Windows still go up and down OK and locks work with key. Any ideas please.