Corvette 1999 air-conditioning vents

Cannot switch to defrost or floor vents. All air comes via dash vents. How to repair???

I can only add that I was with Chevrolet durning those years and we had continus problems with the HVAC control heads.

The flapper valve that opens and closes to direct air to different ducts is controlled by vacuum lines. You could have a line loose or a leak. But initially this is controlled electrically so there could be an associated fuse that has blown. I have an '02 but haven’t looked for this. Does yours have the “Auto” mode switch?

Mine does not have Auto mode. Perhaps that is for climate control systems. Where is the flapper valve located? Where are the vacuum lines under the hood? I saw no fuse specifically for the door cotrol…

Oh boy…I wish I knew more about this…I still have problems overiding the auto mode to get the dang air where I want it.

I hate to say it, but most likely the vacuum lines are under the dash, not in the engine compartment. And the flapper is in the air ducting also under the dash. To be honest, I haven’t spent any time under my dash but I did spend time pulling most of it apart to get to the flasher unit.

I don’t get your reference to the door control…I meant to look for a fuse for the heater/air conditioner controls.

Okay…I just went out and pulled my fuse box cover…lordy…there are quite a few mini relays and relays labeled “cool/fan” etc. Check them all. There are plenty of others that I don’t even have a clue for in regard to the acronyms.

I don’t know how the moderators feel about referring to other forums here…but google up “forums.corvette.forums” for the best advice forums around for the Corvette.