Obvious to many, I’m sure.

[CamperJack]

I have always thought red was positive and black was negative. But I’m half way through installing my Fiamma turbo vent and it has blue and brown wires!

Which is which please?

Thanks in advance!

By the way the hole cutting in the van roof was remarkably easy and it all fits!!

 

[Raul]

I have built a bbq grill in the past with a wiper motor and a potentiometer resistor as a speed regulator. Definitely doable, and a dc motor if you spin it, is a dynamo, it produces electricity. The direction you spin dictates the positive end of wire. Then you can see with the multimeter which is which. In your case it does not matter as the switch is wired to change direction both ways. It only changes position of the switch for blowing in or out.