So to cut a long story short, I'm trying to work out if this page describes a normally open or normally closed thermoswitch. It's from the service manual from my vehicle.
Long story is that, the fan in my little japanese kei class truck is on permanently, has been since I got it, I assumed it was the thermoswitch failed, it was "failed" short, so, first I got a thermoswitch sent from a Japan seller on Yahoo.jp, it was supposed to be for the correct model etc, switch arrived, exactly the one which was advertised, but, completely the wrong size (incorrect thread, way too big ...) to replace the one that's in it, it is however a normally open switch as I'd expected.
So time passes because I'm lazy, but eventually I track down the numbers on the one that is installed, and I find a seller on Aliexpress with them, and get two (because they only sold them in pairs!) sent out, they are the correct size and appear to function, except when I tested them - these are normally closed. I do some more digging, and indeed, that model of switch is supposed to be.
But the fan turns on when the switch is closed, and it's normally closed.... so, something's not right here somewhere (and maybe I'm lucky it never got hot enough to open the thermoswitch and turn the fan OFF).