I have the same problem. Did you find anything out to help?
The 1979 Chevrolet Corvette air flow door might the stock in the position so that air only blows out of the floor vents. The air flow door is located next to the blower fan.
There may be several reasons why the air only blows out the front vents and not on the floor or the defrost on the 2003 Dodge Ram. The fuses may be blown, or the heating coil is not working correctly.
my chevy blazer 1984 the air conditioner blows from down side only.
That is normal, It is a thermostat
The system is low on freon...........
ruud furnace only blows cold air, no heat
Check upstairs heating unit.
The system that controls the flaps that direct the air is not functioning.
blower motor resistor
ihave a 1986 chevette that when i turn defrost on it blows out heat and when i put heater on it blows out only cold air? ihave a 1986 chevette that when i turn defrost on it blows out heat and when i put heater on it blows out only cold air?
Check under the hood for a broken or disconnected vacuum line.
This is the same on all cars. When the air flow is OFF in a section, the it blows stronger to the other vents. In this case the ones for the windshield. This makes defrosting quicker so you can start driving safely sooner.