try closing the other two side vends then see if it works, if not u may have to unscrew the panel there might be something blocking it, if not sell your car
Check the floor heat vent and defrost to see if air comes from them. The vents will be vacuum controlled and a vacuum leak will make the vent doors divert air to the wrong place. Check the entire engine and climate control systems for a vacuum leak.
your float could be stuck
It could be a low charge, but start by cleaning your filter and see if that helps. If the compressor isn't coming on, it could be burned up.
Not overly familiar with the Lumina, but you might have accidentaly disconected them at the bus, or the CD player could be drawing to much power(unlikely)
could be low on coolant
The coil is dirty.Hose it out with a water hose.
the heater core may be plugged up
Faulty Alternator?
I had a similar problem turns out the Alternator was bad.
what could be wrong is you might have a vacuum leak somewhere or something is disconected in the dash that switches to the vents. I had a problem with my 97 blowing air threw the floor and it was a little vacuum leak that caused it
heater core has a pinhole leak! Only shows when under pressure .remove and replace not good to breath antifreeze vapers!
No, they are brown. Don't you know what comes out of them? I think, I could be wrong.