View Full Version : Name that part/sensor?? 86 FWB 307

08-03-11, 12:31 AM
Hey guys/gals,

My apologies ahead of time for not having a pic....but this question is in regards to the OLDS 307 engine for my 86' FWB.

I'm trying to figure out what a particular sensor is, it's located right next to the coolant temperature sensor?........externally speaking, it looks almost identical to the coolant temperature sensor.

I know it's not the oil pressure sensor, because that's right below it.

This unknown sensor is sitting right on top of the intake manifold on the front of the engine, directly next to the coolant temp sensor.

...im thinking maybe a 'oil temperature sensor'...but I cannot find anything in my factory service manual...


08-03-11, 12:59 AM
You have two coolant temp sensors on the 307. One for the ECM/check engine light, the other for climate control operation.

08-03-11, 10:56 AM

The one with the yellow wire goes to the ECM as an input to vary the fuel ratio and spark timing. The ECM may use it as a parameter in engaging and disengaging the A/C Compressor, but there is nothing in my book that says that. The sensor sends a varying resistance value, which the computer can translate into an exact temperature.

The one with the green wire goes to the "COOLANT TEMP" warning lamp, mounted in the telltale. The sensor is basically an on/off switch that grounds the bulb at 260.

08-03-11, 08:33 PM
Thanks for the responses. It's odd how they rarely, if even, mention that in the factory service manual.

08-03-11, 09:19 PM
Diagnostically the ECC is SNS

08-28-16, 09:18 AM
I saw this old post and it and I had the same question about that mystery sensor! Now the temp sensor with one wire has a broken plug/terminal, my telltale light never comes on and the car idles rough when hot so I want to replace both sensors. Would anyone have a NAME of the one wire temp sensor so I can start looking for it to replace? Thanks!!