A/C temp and FSR

[jamie392]

I'm curious what exactly does the FSR control, from what I have read it just controls the blower motor speed. Does it control the temperature at all, like adjusting the internal valve that switches between hot and cold air?

My A/C is fully charged with no leaks, compressor and AUX fan work. The drivers and passengers vents are cold, the middle vent is not that cold. When I set the A/C mode to auto, and set the temp to a low setting, the fan doesn't automatically increase speed. I have to manually increase the speed, so I don't believe the auto climate control is doing anything.

IS there any chance this is related to the temperature in the middle vents?

2004 4.4i

Thanks!