Drivers door lock

[Sunny43.5]

BCM is on the drivers side near the steering column lots of work to get to but i I doubt thats the issue will be , more likely a connection problem . Now this may help get yourself some CRC /WD40 and use the thin nozzle into the key slot and give it a good spray , from memory there is an electrical connection on the outer handle separate from the actual lock loom .

[Syncrotek]

I'm fairly sure it is the convenience module under the driver's seat that controls the door locks, it is possible one of the pins might be loose or corroded in the connector - have a look at the picture in this thread -

Drivers side door lock P1