Rear Door switch / Door adjustment

[Hennie]

My 3 series' back door let the interior light comes on while driving on bumpy terain and especialy when going around a trafic circle. Have adjusted it but problem remains. Does anybody knows where the switch / sensor is located?

[tonton]

I think it is part of of the door catch. You can test this by using a tool to flip the catch as if it had engaged with the door frame.

If the door switch isn't working properly it may be dirt in the catch mechanism or the wire in the hinge area may be shorting / broken.

Anton