Plain Jane OEM nothing to see here rebuild

[RETed]

Yeah, the toggles switch just kills the circuit even if the thermoswitch is triggered on.
Your circuit is wired in series.

I think what you're looking for is for the switch to be wired in parallel to the thermoswitch.
This allows you to turn on the fan regardless if the thermoswitch is triggered not; in another sense, it's a failsafe switch just in case the thermoswitch fails and never triggers!

Side note, I have never come across a thermoswitch (especially a cheap one) that is reliable enough to depend on for my main coolant fan trigger...
Those thermoswitches which rely on a "probe" pushed into the radiator fins are notorious for failing.
Having a back-up switch to manually turn the fan on is always a good idea!


-Ted