A/C temp sensor inside car?

Hello everyone newbie here. I have a 99 grand prix with the digital dual climate control. past year or so A/C works great sometimes and sometimes not so great. I was wondering if there is a thermometer inside the car somewhere that may be going bad? What tells the computer air inside the cab has reached the chosen temp setting? How does the computer know to automatically adjust the heat-A/C based on the temp chosen on the digital display? Checked freon its fully charged compressor is on. Ambient sensor reads outside temp correctly? Any help would be great. Thanks!:banghead:

Welcome to AF.

The automatic climate control (ACC) system has two temperature sensors. The outside ambient air temperature sensor located at the front end of the car and the inside or in-vehicle air temperature sensor located somewhere at the right hand side of the dash (right side of instrument cluster).

On the CJ2 ACC system there is a diagnostics mode you can enter which should tell your if the sensor is open or shorted. The maintenance man icon will flash when a DTC sets.

Thanks! Thats what i think my problem is. Do you know what the sensor looks like and the best way to access it?