You have 2 problems. First, the blower motor running only on the high speed is caused by a defective blower motor resistor pack. Replace it. Second the fact that it is only putting out hot air indicates the temperature control valve is defective or stuck.
what you only need to replace is the blower motor speed controller or also kown as a blower motor resistor.
blower motor resistor
When this happens its most likely the blower motor resister that is bad.......
You have a bad blower motor resister.........
As for why it blows only on the high speed you most likely will have a bad blower resister and for the noise, it could be a bad blower motor, bad blower wheel or trash that is stuck in the blower wheel or housing.......
blower motor resistor thermal limiter is blown. Replace the blower motor resistor.
The Blower Motor Resistor Pack is defective. Replace it.
If the fan only blows on high in the Liberty, check the blower resister. The resister circuit is the most likely cause.
Could be a bad resistor pack at the blower motor Could be a bad low speed relay
the resistor for the blower motor is busted blower works on high with out it
Bad resistor at the blower motor? Bad blower motor switch?
Check to see if the switch is any good . Most of the time it is the switch.