There are some that can’t see the woods for the trees 🤔😉All the 12v PC fans I've used have two arrows embossed on the casing,one for direction of rotation the other for the flow
I can’t remember what your van is, but if you have the tall Dometic fridge with the separate freezer. It should have a built in fan.We might have to fit a fan to our fridge because we have moved to more sunny serviced pitch because it nearer to the facitities for me .