If you have a 'circuit tester' pull the wiring from the back of the heater motor and see if there is a voltage running to it. It might just be a loose wire somewhere.
I'm not familiar with a 93 Escort layout, so can't advise you the best way to get to the motor. Some cars are very simple - couple of screws, others mean taking a load of the dash off
You should be able to get the required info in a good car manual (e.g. one that begins with H and ends with S - hopefully that will get through the advertising censor )