The flaps that direct the air are moved by the engine vacuum, it sounds like you've got a vacuum leak somewhere.
Driver's side front of engine in a plastic housing
what dose the neutral safety switch look like and were is it located on a 1993 buick lesabra at
On top of the transmission where the shift cable is.
try taking out the back seat. that is how i got into my 84 buick lesabra to unlock it
The oil capacity of a 2004 Buick Le Sabra is approximately 5 quarts or 4.73 liters.
on your car it is a defalt mode for air to blow out defrost when there is no vacumn from the engine so you should look for a broken vacum line or see if it has come unplugged on the engine.
The vacuum supply line from the engine is disconnected or broken. When the vacuum supply is cut off the system defaults to the defrost mode.
you can goto http://www.carfolio.com/specifications and choose your make/model & it will give you all the specs you would ever wanna know my 1972 Buick lesabra 4dr weighs 4409lbs
bad relay
loose connector, broken wire, bad sending unit on the pump, etc
Engine compartment, on passenger side. Back box by the water reservoirs.
On the the climate control panel there is are 3 buttons, one says econ, the next looks like your windshield and the next one is square, this is the rear window defrost.