I don't know if this will help. I had the air conditioning quit cooling and found a little (under $15) switch plug that needed replacing. (It sits on a small round sliver tank on the left engine side facing the vehicle) It controlled the air conditioner going on or off. It wasn't switching on when it was hot. Replace it in 5 minutes and the air conditioning works now.+
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
A bad heater blower motor resistor would effect one or more blower speeds other than high.
I had the same thing happening and it was the blower motor. It would come on occasionally and the finally the whole thing died.
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.
blower motor bad or no power to it chech fuses blower switch blower motor
The only relay in the heater system would be for the high speed function of the blower motor. That rely would be located under the hood, on the firewall, close to the blower motor resistor.
This is an indication that your heater core is leaking. To stop the leaking you will have to replace the heater core or stop using your heater.
Could be, heater blower motor has failed. blower motor fuse is burned out. blower motor speed resistor is burned out. blower motor switch is bad. or, if the blower motor works but you have no heat it could be, cooling system is low on coolant. thermostat is stuck open. heater core is plugged. temp blend door actuator is faulty.