The heater core has failed.
The blower resister is not supposed to be grounded. The smoke may be steam from a leaky heater core.
If that smoke is more like steam, you have a leaky heater core.
If it is smoke the heater fan motor has failedORElectronics in the heater have failed ORif it smells like anti freeze rather than smoke the heater core has failed.
Means that your heater core is leaking coolant. Has to be replaced.
Is it smoke or is it atomized freon leaking from the AC system? If it fogs the windshield and smells funny, you may have a leak in the AC/Heater system.
There are heater doors on the heat blower box that direct the path of the heat. Apparently the heater door to the floor vents is stuck closed.
It is probably steam coming from a leaky heater core.
SOUNDS LIKE THE INTAKE GASKET BLEW, OR THE HEATER CORE FAILED.. EITHER WAY, THIS IS A COSTLY REPAIR.
Either the a/c system is freezing up or you have a leaking heater core.............
Bad heater core.
Check the Heater Core? Did it smell like oil or antifreeze. My Heater Core went, started blowing out smoke from the vent. Most Likely the Problem. "smoke" poured into my 1991 when the ac blew out all the freon and froze up the outside temp gage.