Can somebody please tell me what this line is or what it is supposed to be connected to? I have a feeling it has something with my A/C since it only blows through the defrost. I was told it would do this if there was a leak in a vacuum line. Any help is much appreciated




This is a 1984 Camaro Z28 5.0

If the pics didn't show, here are the links...

http://www.flickr.com/photos/25316027@N02/5388888074/

http://www.flickr.com/photos/25316027@N02/5388280707/

Yes its true that without the vacuum hooked up, your heater wont switch from the defrost vents. But those pictures dont look like anything related to the heat vents to me. For the heat vents, theres a plastic air vacuum tank above the brake booster. It has a hard plastic vac line which goes into the car, and also a rubber vac hose which connects to a nipple on your intake manifold right behind your carb in front of the distributor.

Actually, that looks like the metal vacuum hose coming up from the exhaust EFE (heat riser) valve.

Follow it down, see if it hooks up to something like this http://ecx.images-amazon.com/images/I/71px73gqrGL.gif between your exhaust manifold and y pipe. If so, then you run a vacuum line from the end of the metal line, then to the temperature-controlled vacuum switch screwed into the thermostat housing, from there it's T-ed onto a constant vacuum source. The diagram sticker under your hood will tell you specifically where. I think from the line between the carb and pcv.

I dont have a picture because it was about the first thing I unhooked on my car. It pulls your passenger exhaust closed when the engine is cold, forcing the exhaust through the crossover in the intake manifold so the engine warms up faster. But it often makes a horrible rattling noise until the car warms up as it tries to fight the exhaust that wants to go through it. If you leave it unhooked (and make sure theres no vacuum leaks where it would have been connected) then the car will still run fine. I'm not sure if it's needed to pass inspection in CA, but in NY its not considered an emissions piece and not needed.

YES! Thank you!! I'm sure the California standards will probably require it, but at least now I know what it is. But now I'm still questioning why my A/C is not working properly. Thanks again for all your help!!!

Is the vacuum line hooked up as i described in my first post? Rubber hose from intake vacuum to plastic tank, then a hard plastic line that goes into the car where it connects to the heat control. The hard line is bundled with some wires, I dont know the exact routing of it into the car. If its hooked up and still doesnt work, then possibly theres a break in the hard line somewhere, or a leak right at the switch or bad switch. Mine has a bad switch and really struggles to work. I can hear hissing from the switch, so I just unhooked it from the engine and plugged it so the vacuum leak doesnt mess with my engine.

Everything seems to be in order on that end of the hoses. I don't hear a hissing noise coming from the switch when I start the A/C, can you tell me if it's supposed to be loud or if it is faint?



http://www.flickr.com/photos/2531602...5340/lightbox/

I think you guys are on the right track with the Vent controls. But look for a check valve with three hoses on it Its like a vacuum T with a small round canicter on it. One end will go to the harness in the center of the firewall to the controls. The other ends go to a vacuum source and the resivour ball that should be located under the evap canister on the drivers side behind the headlights. Look from under the car. If that is cracked there will be no vacuum being held.

And yes, a smog guy in California that looks for it will inspect the EFE valve.

I'm not sure about that. It's probably a case of different model different engine different year. But it looks like his vac reservoir is above the brake booster like mine.

The next step might be to check the vacuum line where it connects to the back of the heater controls. If theres decent vacuum going to it, then the switch might be broken. If no vacuum, then theres a break in the line somewhere.

I did not even look through all of the OP's pics.
It must be a "where it was assembled" or "who bolted them on" thing. My 84 Z28 did not have that by the booster. My 84, 91 and 89 and my brothers 90 all have the resivour under the evap canister on the drivers side. And they are all a round ball.