Electric Ventilation Question

[PeterC]

Non VX but hoping a sparky can help, if i am allowed to ?.

I am having trouble re-instating our humidity controlled fan.

The fair lady had asked the electrician to move the sensor/pull-cord-override switch because the cord was right next to the pull cord for the bathroom light. I could see that it was getting inadvertently pulled so I had it tied up, un-aesthetically apparently. This move was while the bathroom was being replaced by the landlord. Since then the fan ran continuously. I left it for days in the hope it would settle down. This was in late May when the weather was dry enough. So I had a look.

Now there are three possible connections from the sensor to the fan.
On the sensor these are marked as "-" , "pw" and "+" (pw = I presume is a signal/switched) and also says 12V DC next to it which istr matched the +ve on my meter.
The fan is labelled "-V", "PWM" and "+V.
The electrician had connected the +ve to +ve and -ve to -ve but not connected the PW to PWM. The wiring was a new piece so no hint of earlier use of another core.

My instinct was to connect the PW to the PWM. But not wishing to damage anything I left it alone. I did ascertain that the +ve was 12V (and so was the PW iirc).

The controller is an Airtech DA-CON/25i
On circuit board :-
SMS-5 94V0
E217670
also 1 or vertical line followed by 952

The fan is an Airtech A25 12W
Other markings
12DC 7W IPX7 SELV
Model C200 Date Apr 16 2020
3120 T23
On circuit board :-
A25 SUB 12V
ISSUE4

Does anyone know how these should be connected ?.

I want to resolve it myself as I get the impression these items are installed FOR the landlord BY Airtech and I get the feeling no one should have interfered. I don't want to drop us in it or the electrician. But I will go for the mysteriously isn't working properly option if I have to but of course the wiring will look silly. Oh the tangled web that has been woven !.

Any ideas or better still strong knowledge. Google just leads to pictures and Airtech.