Yes. That smell is the coolant being blown into the air ducts. You might also notice a slimy film on the the glass that is very difficult to clean.
Could be the heater core.
The heater core is leaking coolant.
Sounds like heater core is leaking, replace heater core or bypass
Most likely a film on the inside of a windshield is caused by an engine coolant leak within the heater core.
YES...IF IT HAS STOPPED WORKING IN THE CLOSED POSITION THEN THE HEATED WATER ISN'T FLOWING THROUGH THE HEATER CORE.
The fastest way to defrost a windshield is to turn the defrost vent on without heat or simply open the windows. Another option is to warm the inside of the car by turning the heater on.
Defective heater temperature control valve.
The AC takes the moisture out of the cabin air and that helps clear the inside of the windshield from moisture faster.
Check inside the engine near your windshield if the water drainage holes are open
The parking switch inside of the wiper motor is defective. Replace the wiper motor.
Finding coolant on the passengers side floor. Turning on the defroster and the inside of the windshield fogs up. Sweet smell of coolant inside vehicle.
Either the heater core is leaking, the windshield is leaking, or there is a leak around the cowl. If the water tastes sweet it is a leaking heater core.