Ac and heater wouldn't operate on #5 setting for a while then now blower stopped all together

Due to the age of your vehicle, the brushes in the fan motor are worn out. you will have to replace the fan motor, it is not serviceable.

Fuse maybe

The blower resistor has gone out but if blower is no longer working on speed 5 then either the blower motor is bad as well or the pigtail connector to the motor are bad. Check the plugs to the resistor and to the blower motor for insulation damage discolored or melted wiring.

go for the reostat which is all in one with the blower motor ,expensive part though

Blower housing resistor fried up.You will have to replace whole blower assembly.

you might check your switch sounds like to me that your two lower speed sides of the switch maybe burnwed out.

it is must likely your fan control model -it control's
the fan speed location of model is next to blower

I would replace the blower resistor first. its down by the blower motor.

Remove the hush panel under the dash and unplug your blower motor turn the knob and see if its getting power. If it is replace the blower motor. If your heater seems to work on high but not the other 4 settings. replace the blower motor resistor and pigtail (same general location as blower motor)

if you can reach the blower motor, it could be a worn out carbon brush of the blower motor. if they are, buy a set of carbon brush, learn how to replace them and it would be back running in no time. by the way, when you pull out the carbon brush holder, make sure you dont interchange the position. you can put them back wards and what would happen is the rotation will be reversed. either you reversed the carbon brush holder or just simply interchange the wires that are coming to the motor. i hope i was able to help...