Hi to all, I own a Cinquecento Sporting 1.1 SPI.
I'm trying to understand if displayed temperature is correct.

On unconnected wire of temperature sensor from ECU I read 7.76 Volts (shouldn't be 5?), while on shortcut I read 120mA.
So internal resistor of ECU is 64.6 Ohm.

I connect 150 Ohm resistor instead temperature sensor: gauge says 90 °C.

Brand new temperature sensor: the red one with 16x1.5 thread.
Placed on climatic chamber set at 90 °C (additional digital thermometer says temperature is within 89-91 °C) I measure 270 Ohm.
This means if I use this sensor, gauge will display temperature lower than 90 °C.

I'm very confused.....
Any ideas? could be the gauge not working correctly?
Thanks.

i think with Fiat it is indication only.

i have found that every sensor i have fitted has read slightly different. i fitted one brand new one in the past and it only ever got to about 50 degrees on the dash readout. replaced with another and it was alot closer to 90, but not quite.

i didnt go as far as to check the resistance readings, but i assume they are just so cheaply made and quality control isnt high!

It's only a gauge, not an instrument.

The important part is that you can see it approach the red as a warning to a problem.

D