A question to all but mainly aimed at Bentleytech

I have been looking through the wiring diagrams for our cars and have come across what seems like resistive value switch control.
It looks like there is only a couple of wires to the window switches and for that matter the mirror control. In the cct diagram it looks like when the down switch is pressed the control modules sees a certain resitor value and up another value. same for mirrors one resistive value for pan out and one value for pan in etc etc etc.

Now I come from old school radio/radar/ Sonar electronics on nuclear powered Subs and have only ever come across the normal paired wires per switch function.....meaning a bunch of wires having to go to the control unit

Am I correct in thinking these switches only send a resistive value ( relating to a command) down a pair of wires and not a pair of wires per switch direction?? Meaning minimal wires

 

the window switches have a micro processor board installed in them which in turn sends a signal to the door control module which then controls the window .this does cut down on the amount of wire needed compared to older cars.

 

Thanks.
I presume "normal" testing of the switched using a Fluke/AVO is no longer possible ?
Not that I have problems, I'm familiarising my self, as best as I can, with the car .

 

not sure is vcds does allow this but if you go into door control module you can see if switches are operating through that.

 

I suppose that's the beauty of the VAS 5054A system.