Door Sensor

Does anyone know how the door open sensor works/where it is fitted?

I've spent all day trying to sort out my window problems and have stripped down the drivers door, but can't find anything that looks like a switch.

Most cars just have a sprung switch that breaks the circuit when the door closes, but Afa obviously have to be different.

there's probably a micro switch built into the locking mechanism - that's what most car makers use as it simplifies assembley....