Where is the 2-prong temperature fan switch placement located?

Good morning, FAN98@2023,

Looks like there is a 2-wire sensor located on the top left side of the engine below the throttle body. Sounds like that is the one you replaced. I am only seeing one 2-wire sensor for ECT in my information and a coolant level sensor module on the radiator.

However, I took a look at a GM catalog and there is a 3-wire and a 2-wire sensor available for your engine the 3.1 L82 which came in the Custom and Limited sub-models.

This picture shows a 3-wire sensor on the top rear of the engine.

I have added a wiring diagram that shows the location of the ECT below the throttle body, only 2-wire and I added an image of the location I found in the catalog which is supposed to be the 3-wire.

Try looking at the top rear of the motor, closer to the firewall and see if there is something there.

Unfortunately, because of the age of the vehicle my information is limited. But I will help you the best I can.

If you have time, can you take a photo of the one you replaced so I can see its location? It will help me try and locate this for you since I have a lot of conflicting information.

Do you see a square module on the radiator on the passenger side?

It also looks like with the 3-wire you can get a harness with it and operates an indicator light.

Maybe the 2-wire was replaced with the 3-wire because someone either was trying to fix something or couldn't find the other one.

Take a look and let me know what you see and if you could take a photo or 2 for me that would help a lot so I can see exactly what you are looking at.

I will keep looking on my end and see if I can find any other information for you.

Thank you,
Brendon