I am fixing up a 2003 SS, and I have noticed that the temperature gauge is erratic and wrong most of the time. By temperature gauge I am talking about the little display above the rear-view mirror that has the compass and the temperature displayed, as well as mpg used and such.

What happens is that it will read between 45-30F for awhile and periodically it will go up to around a more plausible temperature.(FYI it reads this when it is in the upper 80's)

I have taken the temperature sensor off(in front of the A/C Condenser) and put it on another Monte Carlo and the temperature read correctly on the other Monte. I put the temperature sensor from the other Monte on mine, and it still read incorrectly.

Does anyone have ideas on how to fix this?

 

You might have a wire grounding out.

This is all I could find with a quick google search...

"The sensor is cheap. GM calls it an ambient air temperature sensor.
If it's not working properly, though, it should pull a code:
P0070 Ambient Air Temperature Sensor Circuit
P0071 Ambient Air Temperature Sensor Range/Performance
P0072 Ambient Air Temperature Sensor C ircuit Low
P0073 Ambient Air Temperature Sensor Circuit High

On the upper left side of the radiator support is a thermistor (a resistor that varies it's resistance according to temperature). It is a two wire sensor. Unplug it and see what you read. It may say something like OC with the sensor unplugged..If it reads OC with the sensor unplugged then the sensor is probably bad. This is a fairly common problem and easy fix. Just replace sensor. You will have to get the sensor at the dealer's part "

 

Thank you for the response!

You see I thought it would send an error code, but it isn't sending one! It might be grounding out somewhere, that is very possible. However, wouldn't other things be wrong if that was the case? I know the sensor is good, because I replaced it.