Only one speed on my heat/ac

[Tyler St.Clair]

I have a 2009 f350 super duty and I noticed that only my low speed works when I turn the switch. I checked all the fuses and they are good, i replaced the resistor and nothing changed. Air comes out of the vents no matter what speed it's set on but it feels like it's stuck on the low setting. Can anyone help me figure out what the issue might be?

 

[blacksnapon]

DATC (dual air temperature control) or EMTC (electronic manual temperature control) ? This is also where you need a high end scanner, it will set a code.