Exodius, thanks for a nice tip on how to fix this annoying problem !
I share the norwegian climate with you (Asker), and have exactly the same problem during the cold season.
When temperature drops below 10C the central locking can not longer be operated with the key in the drivers door. After some minutes of driving all other locks suddenly snaps open. It scared me the first time it happened.
The strange thing is that this delayed opening is almost proportional to the degree of coldness.
Almost a year ago I took the whole locking motor unit out of the door, inspected it, greased it up, but to no avail. The problem persisted.
I have booked time in my motorclub garage on monday, and Im looking forward to implement your procedure.
I can warmly recommend the Haynes manual, which describes the disassembly process in detail
I will report on the results next week !