one of two things , #1, low on antifreeze or #2 , heater core plugged up.
First guess would be a bad ignition switch.
Bad blower motor? Blown blower motor fuse? Bad fan switch? Bad blower resistor pack?
The blower may simply have burned out. If the blower is out then the heater probably still works.
fuse will be in fuse box. it will be labelled, either, heater fan or blower
If the heater fan works on all speeds, then the blower motor, blower fuse, blower relay, and blower motor resistor pack are all good. If the fan runs but nothing comes out of the vents, you have a 'mode door' issue (which might include a bad control head).
A bad heater blower motor resistor would effect one or more blower speeds other than high.
The relay on the heater/blower circuit on a Ford Escort MK6 is probably behind the glove compartment. There are two popular places that Ford puts its heater/blower relay switches. The other place would be next to the blower motor itself.
The year, make and model info would help but generally the heater blower motor resister is located close by the heater blower motor.
Blown fuse? Bad blower motor? Bad blower motor resistor? Bad blower motor switch?
If you are referring to the blower motor squealing, then I would suspect the blower motor bearings have failed.
cabin air filter might need to be changed. located in rear of glove box.
blower motor bad or no power to it chech fuses blower switch blower motor