if there is a lot of snow or ice on these vents located at the bottom of the wind shield under the wipers that could be the problem if you live in a cold environment.
Probably the heater core, it is a beast of a job to do, but is gratifying to say the least. If the is a smell of antifreeze you can almost bet it is the heater core.
check heater motor
They are generally located close to or near by the blower motor.
In the engine compartment. Center of the firewall behind the engine.
also check the AC clutch check for blown fuse... a possible bad blower motor relay
Usually passenger side behind glove box
in my 89 Oldsmobile delta 88 , the heater motor was directly under the center of the windshield under the hood. black circular thing.
Like most internal combustion engines with liquid cooling, the cabin heater going out is normally the cause of the heater coil clogging up, or the blower fan dying out. On the 84 Delta 88s, the cabin air treatment is located under the hood, by the firewall near the passenger. Follow the two large tubes coming from the water pump and radiator to the box itself.
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78000 miles
yes