How to open vehicle Curtins

So I’ve installed curtins in my vehicle and I’ve read you can control them via the vehicle controls, yet when I interact with the vehicle controls I don’t find any options to do so.

What have I missed here?

A door motor, you’ll need a tiny electric motor and then install it as a door motor over the same tile.

Ah perfect, thank you for that. I swear I was losing my mind over that.