I have a 01' dodye ram 1500 van the ac only works on the max setting, but all other settings work. I have looked under the hood and unscrewed the ad's coils connected to the AC Refrig. And they looked fine, then removed the plug Behind the speed switch and it was good, but the 1-3 speed settings do not work. Why is that? Any help is appreciated!

 

Blower motor resistor is blown up.
You'll find it on the underside of the HVAC unit in the cab.

 

Thank you very much