a/c vent problems
 

Just purchased my first vette, 1998, what a great car.
I replaced the LED dual climate moduale because the LED portion did not work, now it does. The problem I have now is I cant get the air flow to change from the dash to floor or to the defroster. The blower sounds like its really blowing hard and I can control the blower speed but the Mode doesn't seem to work.
Any ideas??

This would be better off posted in the C5 Performance/Tech section, or the C5 General section.

What model number did you replace your original HVAC unit with? Your 98 needs a 09352181 which was superseded by part number 16254311. Either one should work for you well...

What did you do with the original unit? I'd be interested in it...

Do a search on battery acid damage, FAST! Pull the battery out, and look under the tray for signs of leakage/acid damage. Hopefully, there isn't any.
Barring that you didn't use the wrong part number to replace your HVAC unit, you have a vacuum problem. There is a hard plastic vacuum line that runs off the back of the intake to a canister inside the passenger fenderwell area, then into the cabin. This vacuum is what your HVAC uses to move the door from face to feet to defrost......
Start there.
:thumbs::cheers:

I have to return it (core charge)..The one I purchased is for 97-04's

I have the battery and the battery seat out, I dont see any acid damage, it all looks really clean. I'll try finding the vacuum line, is this a line with a clamp of some sort or a screwed fitting?

It's inside the wire loom. You can't see it. Feel along the backside of the intake, you will feel a hard plastic line the runs toward the passenger side into the wire loom. That's the line.
Take the passenger fender well access panel off. You'll be able to see the line and where it comes into the canister.
Open up the entire wire loom, and trace the line from the canister to the intake. Feel and look for cracks.
Personally, I would just go ahead and pull the line from the intake and the canister, and replace it with rubber vacuum hose now. That's how I fixed mine. The hard line is going to break eventually, if it isn't already busted.
To get to the back of the intake you either have to unbolt the intake and slide it forward. Or, if you're hands and forearms are small enough, you can get back in there and feel your way to removing and replacing the line.
Let us know what you find.
:thumbs:

How do you get to the vacuum line behind the intake manifold:)

vacuum line
 

I have the same problem, How did you get to the vacuum line behind
intake manifold?

Ok I may be off base here but I remember somewhere there is a reset. Have you ever run the codes on your car? Then cleared them? When you do the HVAC codes you will hear the "flappers" open and close to cycle through the system. Before I would start going through the vacuum hose I'd try clearing all the HVAC codes first. Did it work before you changed the the control? Bill