but some thermoswitches have 1 or 2 pin connections like temp sensors.

in cases like this, google is your friend my friend... you may want to see and download from the mitsubishi website. i think it is under the "other troubles" threads. the website language is something like kazakhstan or russian, etc?

try this also:
sometimes the thermoswitch and temp sensor are close to each other located at the upper hose outlet. disconnect the wire from one sensor. start engine and let it approach operating temp then watch if the temp gage rises. if the needle doesn't move then bingo!