Mine works great but in the winter I know when I started putting a piece of insulation covering my trans cooler in the front lower bumper hole my temp gauge for outside is all mess up shows it is +20 out when it is like -20 to -30 out. But soon as I take that piece out it is back working bang on. 🤔
Outside Air Temperature (2500/3500 series with Diesel Engine)
The Ambient Air Temperature Sensor is located in the Passenger Outside Rearview Mirror and varies it’s resistance with temperature.
The Engine Control Module (ECM) reads the resistance value to determine temperature. The time of and rate of the temperature update is based on an algorithm in the Engine Control Module (ECM) software. Factors such as, last reading, current reading, length of time vehicle is been off/on, power mode, vehicle speed, driven distance, and sensor location are all considered by the Engine
Control Module (ECM) to know when to update the displayed temperature on the Info Display Module.
2500/3500 series trucks with diesel engines are also equipped with an Ambient Air Temperature Sensor located behind the grille. This sensor is not used for any purpose and does not affect engine control operations or outside air temperature display functions in any way.