The heater/ac only works when set on "high" no lower speed settings work on 2001 Dodge Caravan

The heat and A/C work fine. When I turn the knob to set adjust the heat/AC from low to medium, nothing comes out. When I set the speed to "high/full blast" everything works perfectly.

How can I repair this problem?

Asked by for the 2001 Dodge Caravan
blower resistor is bad. have it verified by a shop and get a bid.

Thanks for the help and response, I apprecate it. From other research this seems to be the problem and an easy fix. Larry