The dash vents on my 1999 Camry do not blow air. Air does blow at my feet. What could the problem be?

Your blend door motor has failed. Not sure if the '99 is cable driven or motor driven. But it has failed either way. Here is a short video on the repair of an older model. You will at least be able to see how much of a job it is. https://www.youtube.com/watch? v=hXLN9jUZsP0

I would check the cabin air filter also. If it is dirty, it can cause air not to circulate properly through your vents. Here's a video on how to change it: https://www.youtube.com/watch?v=0xcBGnP1vNY Good luck and I hope this helps.

My 99 Camry had a similar issue except it would let just some air out of the right side, very little on the left side with an annoying whistling sound. The problem is Toyota put in a screen but no easy way to clean it. If you shine a light in the center vents, you can see it way in the back. There's two solutions, you'll need to remove the vent adjusters for either one. 1.) If you have an air nozzle with a long extension, (Harbor Freight sells them) turn the psi as high as you can, shove the nozzle all the way to the back and blast away. It maytake several tries. I had to get the nozzle all the wat to the screen before I got good results. 2.) The other fix is to take the screen out altogether. Use a long screw driver to poke holes in it, then use a long needle nose pliers (Harbor Freight again- no, I don't work for them) to pull out the screen. I didn't do mine this way but it seems like it would work if you don't have an air compressor available. I'm obviously not a professional mechanic or I'd have better tools than HF. LOL. Good luck, hope this helps.