the other day I was having problems with the air not coming out of the front vents. a hose was loose so I fixed it. it started to go out again and even when the a/c was in the off position I would feel some air coming out of the vents. now when you turn the controls on air comes out of every vent including defroster and floor. not a lot comes out of the defroster but it still comes out all areas no matter what setting you turn it on. i pulled it back out to check the vacuum lines and they are all connected still. any clues as to why it would come out all vents at the same time and not change or just come out of one? I'm a little stumped with this one. I've read a lot about just coming out of defroster or front vents but not all vents at the same time.

 

check for a vacuum leak in the engine bay low vacuum may cause the problem your having

 

thanks, i'll try that. i hope that's all it is.

 

still not working. I checked any hose i could find in the engine area and everything seemed to be o.k. all the a/c components are a few months old except the blower. the air blows really strong from all the vents and the floor at the same time but still comes out a little from the defroster up top. I still can't get it to just come out one or the other. it sounds like it's switching but doesn't. I can see the flap a little by the heater core and it seems to just hang and not move really. not sure if that has anything to do with it. I really hate to take the entire dash back out. i also hear a loud sounds around the fender of the passenger side, I think around the blower. I don't remember hearing a loud sound before. even when it shuts off i still hear it for a while. all the hoses on the back of the control unit are hooked up.

 

I checked again and still can't find anything. it isn't blowing as hard as I thought out of the main vents. blows very little and still comes out of the defroster at the same time. I took the hoses off and the air stayed the same.

 

we found some air coming out where the accumulator/ drier goes into the black box area on the wall. when you shut off the car you hear a sound coming from there and the accumulator/ drier instantly goes from cold to hot when you touch it, after it shuts off. never had that happen.

 

the air comes out of where the red arrows are the the blue is where it gets hot after it shuts off. the red is also where the noise is coming from.

 

o.k.. I pushed the flaps that are under the passenger side by the heater core up. they were hanging down and the panel that covers it couldn't be bolted back up b/c it was hanging out. the hissing is gone but now the air only comes out of the defroster so I'll search that.

 

take it back... a checked hoses again and nothing. I moved that flap back the way I found it and the air comes out all vents again and the sound is back by the accumulator. also there is not a lot of force with the air even on max when it does come out of the main vents when i moved the flap.

 

All the vent doors that direct air flow are controlled by vacuum actuators. If you change the selector switch from say defrost to floor to dash vents, etc. what happens? From what I am reading, no matter what position you set the switch it, it just blows out all vents?

 

your correct. I can move the switch from max to defrost etc. and it still blows out all vents. the pressure of air is also not as strong as it was. max is just the same as normal and it use to blow harder. I checked the hoses on the back of the switch and they seem fine. I played around with them for a while and nothing. I don't hear any hissing sounds from inside. I could get my hand up in the area of the vent doors and it would change some. the door was hanging out from under the passenger cover and the cover would bolt up. I pushed it back in place and then I only had defroster. when it comes out all the vents you hear a loud sound by the drier in the engine area. when you shut it off and the car it makes a loud sound where the drier goes into the box on the passenger side and air comes out where it joins. it also goes from cold to the touch to hot instantly while this sound is going on.

 

I noticed today that when driving about 55 mph air/ heat comes through the vents even with it turned off.

 

I had EXACTLY the same symptoms on a 84 Z28 (w/air) years ago. I no longer have the car. I found the problem was caused by a disconncted vaccuum line under the hood due to a dried up hose. There was a line running from the carburator, to a small diaphram on the drivers side near the master cylinder. The diaphram controls the lockup on the torque converter for that year. Anyway, there was a small tee fitting just before the vaccuum line gets to the diaphram, the other line connected to this tee was the line that controlled the ventillation. Also, the source for the vaccuum must be plugged into a 'non-ported' line on the carb. This just means it has vaccuum at all times. A ported vaccuum line would not have vaccuum when the throttle blades were closed (idle). If I can find any pictures of this area I will post them later.

 

I think I may have found it. after taking the entire dash and console apart I found a pink line that was pinched and I tested it with the dash off still and the flaps move and there's more air. A lot of trouble to get to it but better than taking it to a shop.

 

That was it. I have most of it back together and even got the flap in the correct place and everything works.

 

Awesome, good work. Those problems are always a pain in the butt to find.

 

thanks, I was really dreading taking the dash apart and pulling it out. I'm just glad I found it.