My GTA when you first put the air on it blows out of the windshield defogger ports, and after I go down the road for awhile it will start to blow out of the correct vents in the dash. Anyone else have this problem and if so how can I fix it. any help would be appreciated thanks

 

Never heard of it CHANGING like that..but i know if the dash was removed, and replaced and hooked up incorrectly, things will blow backwards. Such as..putting my heater on, INSTEAD of blowing vents like it should, it blows leg toasters and defrost.

 

sounds like there is a vacume leak somewhere in the dash or the controler

 

my car does the same thing. it's a vacuum leak somewhere in the vents. i'm pretty sure you have to rip the dash out to get to them so thats why i just deal with it.

 

not an expert here, but i'll try to help from my experience...

what's probably causing your problem is the "manifold" type connection on the back of the vacuum select (?) switch on the control head... probably have a leak there, and hard to detect, if you don't hear an apparent vacuum leak... usually the air comes out defrost, by default, if all else has failed. i would check that manifold connection first, before i'd consider taking the dash apart for all that...

first, it's easier to work around the a/c head unit if you take your stereo out... up to you. then you need to unbolt the climate control system (a/c head unit). on the back of it, you'll see that manifold type thing with about 5 vacuum lines on the back of that selector... you have to pry off those little captive washers and the thing comes right off. now you have to make a choice... easy or a little more difficult... easy - take a q-tip and apply a little vaseline to the inside of those vacuum lines, put it all together and try it out. sometimes that will solve the problem. difficult - separate all those tubes individually (cut that manifold thing up), and re-attach each tube to its respective port on that switch and put a tiny zippy-tie on each one for security...

my results were that i separated all the tubes and re-attached them, and haven't had a problem since. air goes where it's supposed to every time.

you can replace the whole "harness" with all those vacuum lines, it's very cheap, less than $10, but you'll be taking your dash apart to do it...

KAM

 

Umm...

Isn't that normal for our cars?

By default, the vents blow out the defogger areas, I'm assuming so that if you do lose the controls, you can at least defog your window.

When you select MAX, AC, yatta yatta yatta, a vacuum is directed to the gates inside the ducts and what-not, and the air blows out the appropriate port. The blower motor is going to start blowing faster than the gates can open and close, so some air will almost always come out the defogger ports first.

Now, if it takes a really long time to get air to go from one port to another, then there may be a leak somewhere. I suppose you could just rip out tubes and replace them until you find the one that fixes it.