Yes, to clarify, you need an automatic climate control system in order for the system to use inside and outside air temps to adjust the a/c settings automatically. In your (and my) manual system, the vent setting and the fan setting are the only factors.

 

I have a 2005 F350 with climate control and my external sensor is way off -- reads 61 degrees when it is an easy 85 outside. Plus the A/C is very weak. Dealer has replaced the sensor (no help) and is now getting a complete control head for the Climate control. Hope that does it.