Incorrect ambient temperature reading

[maxiz1]

Hello guys,
My instrument cluster middle LCD shows incorrect reading of the ambient temperature where it displays 23 degC but the outside temp is actually somewhat 30 deg. This caused my HVAC not blowing enough cold air and I have to do manual adjustment to it.

I suspected the exterior temp sensor had gone bad (G17 in front of the radiator), but when I checked the reading through the climatronic unit channel no 59 (audiforum HVAC hacks), it does shows more or less the correct temperature. And no fault codes are shown through the scantool.

So my questions are:
i) Which sensor feeds the temperature value to the instrument cluster?
ii) How to test whether the sensor is working or not?

Thanks.

[doughboy17]

Just FYI, my sensor has always consistently read 4d F high. I just subtract 3-4 d F from the reading.

[Articus]

It's the fresh air intake sensor inside the HVAC. Located underneath the cabin air filter.

[rodgertherabit]

good info, im having the same issue.