Fan switch works on only one speed

What Steve said plus, double check your cabin air filter to make sure it's not clogged and forcing the motor to draw more amps. Also, perform a current draw test on the motor to make sure it's not drawing more amps...that'll burn up the connector

First you have to figure out if you are missing power to the blower motor, or ground to the motor. The motor gets power from the key switch, and the fan switch grounds the resistor to change speed.

your control switch ,where you turn on up to high position, is bad. replace it

Wire between fan motor & switch disconnected or fan motor bad. Check and/or replace

get a new fan motor resister.

the blower motor resistor if i remember correctly is behind the glove box ,once u remove the glove box u should see it . make sure u check the wiring connector, i have ran into a few that has melted ..had to ret a replacement from chrysler that had a bigger supply wire. hope that helped you!!!

Your fan speed dropping resistor is burnt out, it is located near the blower motor.

Sounds like a defective speed control resister.

if you have checked the switch as recommended, it is most likely to be the heater resistor which contols the diffrerent speeds. it is
normally fited near to the motor and is a squarish block with multiplug on it and coils like springs in the centre of it, look at the coils they may be burnt out.hope this helps

there is no computer control unit, what u need to replace is the fan speed control resistor module.