Ac & heat

Did you replace the blower motor resistor pack? Try to isolate the actual malfunctioning part before replacing anything, guessing can get expensive and no guarantee problem will get fixed. A voltmeter will let you test the fan speed setting switch and the resistor pack as well as the fan itself.

If you car has "automatic" a/c, where you set a temperature and the system maintains the setting, it is likely your evaporator is plugged with debris on the outside. On these cars, all incoming air goes thru the evaporator then is heated (if needed) the car manufactures discovered pollen, animal hair, etc gets stuck on the moist evaporator and eventually plugs the air flow....so they started installing "cabin air filters" that catch all this crap before it plugs the evaporator. If you car happens to have a cabin air filter then change that....if not you need to clean the front of the evaporator.