I have a 98 z28 and the controller switch to adjust my AC, defogger, etc. doesnt work. It appears the AC is coming on, but it's only coming out of my defogger and vent near my feet, and not coming out of my main vents. Is it a fuse or the control panel itself? Thoughts?

 

That AC vent control should be vacuum operated in a 98.

Probably a leak of some sort that has kept the blend door from moving.

 

When there is a vacuum problem the system defaults to defrost and feet.

Shoebox has the fix on his website.

http://shbox.com/1/4th_gen_tech2.html#HVAC_vacuum