No
Friction
if the blower motor still works, somebody probably bypassed the heater core in the past.
A stuck or incorrectly installed thermostat.
The year, make and model info would help but generally the heater blower motor resister is located close by the heater blower motor.
Yes it would be unlikely an electric motor coincidentally exactly matched the resistance of an electric heater.
fuse will be in fuse box. it will be labelled, either, heater fan or blower
plastic cover for heater motor
Remove the wiring harness from the back of your heater fan motor. Remove the heater fan motor retaining bolts. Remove the fan from the front of the heater motor. Reverse the process to install your new heater motor.
Heater motor speed resisters are usually located close or nearby the heater motor.
Your motor oil going bad would cause that. That is in the crankcase, not the transmission.
it is possible for heat from combustion to cause an engine to overheat quickly depending on where the gasket is blown, but i would look for a lack of coolant circulation first. if your coolant is not getting out of the motor and into the radiator it will overheat very quickly.
Remove the wiring harness from the back of your 1994 Chevy heater fan motor. Remove the heater fan motor retaining bolts. Remove the fan from the front of the heater motor. Reverse the process to install the new heater fan motor.