Help ! 12V lighting plus where pick up in the interior

Desperately looking for 12V Plus (only at night so Illumination Plus) to tap in the I3 interior. It should be used to connect ambient lighting. Should only shine at night. Where Can I find it. Do anybody have a wiring plan ..... ?
Thank you in advance for your help Berni Germany

From the diagrams in https://www.facebook.com/groups/BMWi3/permalink/4280574412016387/ it looks like the high-beams and turn signals get power from the Body Domain Controller. The LED low beams get continuous power from the fuse box in the passenger footwell and are switched on and off with CAN Bus (K-CAN3) messages from the Body Domain Controller.

that means no 12v switched on the light switch in the interior available - where else can it be tapped?
thank you very much and merry christmas

Berni

My guess at a solution is to use the power signal to the license-plate lights (or whatever tail lights come on at the desired time) to turn on a relay that switches continuous power to the ambient lights. Check the voltage across the lights and if it isn't battery voltage, it is probably a current-limited LED output from the Body Domain Controller. To use that you might have to cut the wire and put your relay coil in series with the LED.