Does anyone know where this switch is located on the tailgate door?

I have started having problems where occassionally the central locking will activate (lock) after I have unlocked and opened the tailgate. This re-locking happens as if the tailgate has not been opened at all (ie after 30 seconds or whatever) and not immediately.

I am presuming the door switch is on it's way out but for the life of me I cannot see where it is physically located unless it's inside the door trim near the lock itself.

Any pointers would be appreciated. Thanks in advance.

Also does anyone have a link to where I can find a wiring diagram????

Cheers
Alan