If the car heat has a fresh air setting, then it could be drawing air from outside of the vehicle. The fumes are most likely coming from a problem under the hood.
Possible leak in gas line. Must be some sort of air leak in the heater box under the hood. Heater is pulling fumes into car through the leak in it.
Breathing fumes from antifreeze cannot be good for your health as antifreeze is poisonous. If you are smelling fumes in your car you probably have a heater core leak. I recommedn you have this repaired ASAP. The only fix for a leaking heater core is to replace it. A very labour intensive job that is quite expensive.
you have a bare wire touching on your blower motor
exhaust leak or a possible fuel line leak
The relay is bad.
The ONLY way to get the smell of fuel - kerosene, diesel, gasoline - out of your clothes is to put them in the sun and let the fumes evaporate. Every other remedy is a waste of time.
Only reason would be that the heater core is leaking.
More than likely your heater core is leaking. The only fix is to replace it.
Only if you want to smell the fumes all the time. Code says it should be through the roof or above the edge of the roof.
You are likely in an antarctic region.
the control cable probably came off the connector