I have a 99 chevy astro recently the AC and heat will only come out of the passenger side footwell. The heat started doint this off and on last year. Now the AC is doing the same thing. Does anyone have any ideas on how I can fix this?

 

You might look for a vacuum leak in your air control system. The HVAC control head uses vacuum to switch where the air comes out, and if a line is leaking, it goes all goofy. Begin by checking for a leak where the main supply line connects to the intake manifold and trace it to the vacuum reservoir (black plastic ball with a vacuum line going to it). Also check the vac. harness that runs over the engine cover under the dash. You can see it if you remove the console trim over the engine cover. You might even need to pull out the HVAC control head and check for leaks there. If all this fails, you will need to check the individual lines to the various actuators and also check the actuators themselves. I hope you don't have some kind of debris down inside the HVAC duct work. Good luck and God Bless.
Revredneck