Night mode consists of a second mesh that is invoked at night. Usually this takes the form of a set of planes that cover the existing windows. Note that for performance reasons sharing the texture file used with the main texture file is to be preferred so place the night.im file in the same folder as the main.im or body.im and texture file. The secondary .im file can be created in Blender by sizing the plane to just cover the window or part of a window in the case of emulating curtains and referencing the normal texture file. When creating the night.im file in Blender first move all the window planes to a separate level adjust the emit slider see under textures for self illuminating then export the night.im file.
Note any colour can be emitted not just white.
Use 86627:2474:3 or later as an example of the config.txt file.