fan switch that i can use

[Madmark]

As some of you know I've done fan conversion and I have adjustable switch which I'm just not happy with. It works well but the probe and its copper wire isn't very long so the adjuster is just bolted in engine bay and doesn't look like it'll stand getting wet much so can anyone recommend a convesional fan swith with 1\8th npt thread that I can fit into a 38mm adapter

Ideally a twin stage switch\thermostat