What, no one has even suggested to check the switches for the interior lights?..
Well, I have checked those as well. They sometimes malfunction and are going to be changed for new ones, but they are not the problem.
My guess is the fault (Or faults) are in one or both front door locking motors, or something called a microswitch on the lock itself or maybe in the control module.
I donīt know if anyone here know anything about these things.