High water temperature alarm

[kippers26]

on my thermostat housing there are two sender units one is wired to the temp gauge ( engine runs @ 90 c ) the second appears to be wired into the low oil pressure buzzer. Am I correct in thinking this second sensor is a high temp alarm, and if so can someone let me know what temp it sets the buzzer off at, also is it possible to test this sensor in situ.

 

[nimbusgb]

Short the second wire to the engine block ( assuming a common earth engine ) if the buzzer goes off with the ignition on the circuit is working. No way to test the actual sensor without putting it into boiling water if its trigger point is under 100C or a heated oil bath if higher.