Umm, it's basically a resistor who's resistance changes with temperature. (Thermistor)

Are you saying I can't uninstall the part and measure its resistance across the leads?

Paper clip equals almost zero resistance equals PCM thinks engine temperature is high.

I can put a DVM across those two terminals on the ECTS anytime i please and get a resistance measurement.

I know this because I have.
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Coolant Temperature in the S cars is measured by that two wire ECTS. Always has been.

Up until 95, they had two temp sensors. The two wire sensor fed the PCM and a one-wire sensor fed the dash gauge. In 96, the separate dash sensor went away.

 

The sensor pair consists of two separate negative temperature coefficient (NTC) thermistors, one to each lead from the unit housing. Measuring from lead to lead places both thermistors in series, so it will not measure each one separately.
The double sensor continued up through at least '99. I replaced the unit on my 97 SC2 and my '98 SC2 (which I have owned since 2006). One of the sensors goes strictly to the dash gauge, while the other goes indirectly to the fan relay. The AC separately triggers the fan when the compressor cycles on.
Incidentally, if the fan motor dies (as did happen on my '98), the car will overheat when not moving, and the AC will quit blowing cold air. When the car is moving, however, everything will appear to work normally, as there is enough airflow to cool both the engine and the AC condenser.

The best way to get a proper reading is to first measure the resistance from each terminal of the sensor to ground with the engine cold. After the engine is fully warm, repeat the measurements. The resistance at each terminal should drastically drop. If either side does not change significantly, replace the sensor. GM used this dual sensors on certain vehicles from the mid-1980s up to the turn of the century. I had the same identical sensor on a 1986 Buick Somerset 3.0l. Same radiator fan, too. Both parts were loaned to my 1998 SC2 until I could get replacement parts from AutoZone mailed to Guam in 2007.

This has been mentioned before, but if you suspect the sensor, first swap the relay with another. All the black relays are identical, as are the grey ones, and can be easily swapped to rule that out. In my 20 years of owning four Saturn's (still have three!), the only cooling system parts that failed were the sensor and the fan motor--both on an SC2 that ran the AC ALL the time on a tropical island. Now if only that were the case on my dead '09 Aura 3.6l....

 

Yeah, no.




Might have been the way you say on other GM cars, I don't know.

Not that way on Saturn S cars. 5V across variable resistance that decreases as temperature increases (neg temp coefficient of resistance).

5 volt straight from PCM through voltage divider to one of the pins, the other is ground. Measures voltage drop which, by internal lookup table, corresponds to temperature based on assumed calibration of ECTS.

Please don't make me go get a real wiring diagram that shows both pins directly connected to PCM terminals. Really not in the mood.

 

lol!