A week ago, the courtesy lights stopped working. Manually I could switch the passenger compartment lights but a opened door didn't switch them on. After some days i found the problem the courtesy lights timer (a little blue box, placed under the back seat), one of the wires (pin 7 of N10) was torn. For my luck this was a ground signal from G63b (it comes from the body of the car). After i connected pin 7 with a ground, everythink worked perfectly: when there is a opened door the courtesy light stops after 200s, if you close the door the courtesy light stops after 20s. If you engage the ignition key the courtesy light stops immediately.
But i found that when the ignition key is already engaged or the engine is working and i open a door, the courtesy light switches on, but when i close that door the courtesy light doesn't switch off. Sometimes the courtesy lights switches off after 20-30s or some minutes, in this situation. It's very annoying problem, because during a night if you are driving somebody, when he comes out of the car, i have to turn off the engine and after that to start it again, because the courtesy light disturbs me.
I think that the courtesy light timer is the problem or the general door locking system. On the control panel when i open a door, the red light switch on, and after i close the door that light switch off.