Temperature gauge not reading when engine is hot

Good morning,

Can you give me the voltage reading at the temperature sensor on the cylinder head between number 1 and 3 cylinder spark plugs?

https://www.2carpros.com/articles/how-to-check-wiring

If it is reading okay when it is cold and normal, I am wondering if you either replaced the wrong sensor or you installed one for a light instead of a gauge.

There is a coolant temperature sensor on the intake by the thermostat but that is not the sensor.

https://www.2carpros.com/articles/how-a-coolant-temperature-sensor-works

https://www.2carpros.com/articles/coolant-temperature-sensor-cts-replacement

I attached the part selection as well. The 2 look the same but are different.

Roy