A/C blowing only out defrost vents
 

My 96 LT1 suddenly stopped blowing air out the main vents. Even when pressing the Auto and other modes it still only blows out the defrost vents. It blows cold but ends up fogging up the windshield. Has anyone experienced this or know what is wrong?

Thanks for your help!

RE: A/C blowing only out defrost vents
 

hhmmmm....i know that in chrysler productsthe somewhat archaic item used to control this is called a blend door actuator. it basically opens and closes certain little doors to allow for air flow to different areas, and it should be around the blower housing itself. on the cars that i have seen it on, it is comprised of little plastic arms. very well could be your culprit.

RE: A/C blowing only out defrost vents
 

Thanks for responding. I will look to see if that is the culprit. It worked when I first bought the car and then slowly started becoming difficult more and more over time until now it doesn't work at all. I guess at least it isn't the compressor. It still puts out cold air just on the windshield.

Thanks again for the help.

RE: A/C blowing only out defrost vents
 

let me know how that works out. like i said, on non-vettes it was called a blend door actuator arm

RE: A/C blowing only out defrost vents
 

I have the same problem with my 96. I've heard it's pretty common and that it is due to the vacuum controller. I bought a new one but havn't had a chance to install it yet....

RE: A/C blowing only out defrost vents
 

hmmm..so its vacuum and not mechanical? interesting.

RE: A/C blowing only out defrost vents
 

Yes, vacuum controllers used to control the direction of the air flow in the C4s...IIRC, you'll need to pull that dash off to replace it, but it can be done.

Mac

RE: A/C blowing only out defrost vents
 

Through my research thus far I was able to determine that it is related to the vaccum system....not mechanical. Luckily our Service Director used to be a Chevy Mechanic and he is going to help me with it. The only thing that doesn't make sense is that it suddenly started working again for a couple days and then stopped. Could it simply be a vaccum line disconnected, degraded or punctured? When I bought the car the key fob wasn't working properly and they had to replace the transmitter in the dash. I guess they could have damaged a line then.

I will keep you posted what I find out. I have to do something before it starts to really get hot.....pretty soon here in Florida.

Thanks for your responses.

RE: A/C blowing only out defrost vents
 

I have a 93 that was doing the same thing. It turned out to be the little plastic manifold for the cruise control and the ac. It is located under the fuel rail cover on the passenger side. It was cracked. I replaced it and the ac has been working fine for last two years. Dont know if that will help, but it might be worth looking at. If not at the plastic manifold, maybe one of the vacuum lines.

RE: A/C blowing only out defrost vents
 

c44me, if it comes and goes, it sounds like you could just have something that is wiggling loose and causing the problem, perhaps a vacuum line, or a fitting somewhere in the system?