coolant/oil/other temp sensors vas

[K567]

3 sensors
i know green is coolant
brown has something to do with aircon (not used )
what does the blue one measure? is it coolant or oil fed

[Wee_monkey1987]

on my VTS blue is coolant temp sensor and sender for dashboard dial, green is for signalling overheat LED on dial

[K567]

so they both measure coolant temps?

[Wee_monkey1987]

yeh the green one is a thermocontact sensor that's earth when there's a loss of coolant in the system at around 116deg.C

the blue is a negative temperature coefficient thermo-resistor where the resistance in the sensor decreases as the temperature goes up - hope that helps

btw my source is taken directly from the Bosch Citroen operating manual for ME7.4.4/M7.4.4 system i believe magneti marelli are the same from what the Haynes manual says