At the firewall on the passenger side
Yes, if the blower isn't working. If it turns out to be the fuse, and it blows again, you probably have a bad blower motor.
Might be a bad heater control
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
The master cylinder contains the reservoir for the brake fluid. This is where you would add it on an 1990 Cutlass Supreme.
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.
It seems that they most problems with the 93' Oldsmobile cutlass supreme would be the engine and the break. Those seem to go out the most on this car.
Sometimes the Cutlass sedan and the Delta 88 would share the same wheel design.
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.