My heating suddenly stopped

Can you determine if this is blower motor failure, blown fuse or blocked heater hoses? One way to determine this is with heater control set for max heat thru vents. At speed, most ventilation systems will allow forced airflow with warm to hot airflow thru vents if the blower motor isn't running. If you can feel warm to hot air from vents, this should indicate heater hoses are not blocked. Is the engine temperature correct and not a worn out thermostat? Radiator hoses should feel hot. Both heater hoses should feel hot as another way to tell hot coolant flow thru the heater coils. A drive with rear windows partially open will allow heater ventilation to draw moist air from the interior.