Climate control only blows thru heater and defrost - no vent

Best guess. The system is both electrial and vaccum.
A long the way you programed the climate controll system to these setting. You have set codes into computer. You need to refere to the owners manuel. If you do not have a manuel. Remove the fuse from the fuse panel. Turn the car on but do not start it. Pull the fuse. Turn the car off. Reinstall the fuse. And start the car. Should reinstate the factory codes. Good Luck.

You are having a very common problem with your Corvette. The vacuum controller is on the driver's side, on the back side of the fire wall about as far as you can reach under the dash. It is a real treat getting to it. The problem is that the soft rubber nipples on the controller that the vacum lines connect to are collapsing under vacuum. The controller needs to be removed to repair it. The nipples need to be cut off about 1/2 way down with a razor blade. It is best to remove the driver's seat to get to it. The '95 and '96 models suffer from this problem. Go to The Corvette Forum to get more answers on Vettes.

My 2 cents,

GWH

Somebody needs to make a video of how to get to the vacuum lines that are back behind the dash and I don’t mean just the top cover I mean taking out the whole dash and explain why what’s going on and it’s entirety from start to finish