I have been told that when the fan blower only works in the last setting, it is usually the result of a bad fan resistor. I ran across this question trying to find where the location of that resistor is. The Haynes Repair Manual for the Dodge Spirit does not show the location...
You need to replace blower motor resistor.
replace the blower motor switch
Failed blower motor, resistor or switch.
Blower resistor pack broken?
The blower motor speed resistor is burned out.
when a blower motor only works on high, it is usually due to faulty resistor board. Should be located in the duct near the blower. the purpose of this is so the air blown by the blower keeps the resistors cool.
replace the ignition switch
The blower motor resistor pack is defective. Replace it.
Blower fan inoperative or only works on high speed.
check coolant level
If you are saying that the blower motor only works on the high speed setting, then the Blower Motor Resistor is defective and needs replacing.
Because it needs a new blower motor resistor.