Urgent questions about PCV on Volvo S40N T5

[AHHL]

I have noticed that previous owners had made a own self made T-connection from the engine to the crankcase with one hose running directly out into the atmosphere under the engine and the other hose connected to the PCV. When cleaning the crankcase I also note that the electric cable that is supposed to be connected to the black plastic top of the PCV was also disconnected. As the matter of fact it is nowhere to be found in the engine compartment. I was looking from below and from above but couldn't find it.

I do not know if the cable goes to a sensor in the crankcase, a small pump or what it does and therefore I seek answers from someone more knowledgeable than me. Preferably article number, where and how to connect it and what it does.

When i bought the car I did not know much about cars and I have been learning ever since. Because of this and as well as three car workshops including Volvo's inability to note or report this, the car has thus been driven without a properly connected crankcase for several thousand miles, what can the consequences of this be?
The reasons for me starting to investigate this in the first place is rough idle, the engine loosing power and dropping in RPM when coming to a stop a slowing down, sometimes even dies completely and very uneven functioning in lower gears and RPM's. The symptoms have gradually become worse and worse.

Attached a diagram from Volvo of the PCV. The electric cable I'm pointing to in the text is part number 11 - 14. Also a Picture of my PCV with description.