Air conditioning knob doesn't blow on the lower settings.

[7thWheel]

Hey all. My air conditioner/heater doesn't start blowing until I turn the knob to the higher settings. settings 1-3 don't cause the air to blow at all. When I switch it to 4-6 it cranks. Is this a fuse issue or do I need to replace something? Thanks in advance.

 

[02LTD2.0]

Blower motor resistor has failed.