On each option at the top lever on my a/c heater control when I switch it to a different setting I hear an air leaking noise. I beleive it a vac. leak. How hard it it to take this out and what would I need to do to fix it? would this cause some of my vents to not blow as hard as the others. Also how hard is it to swap a whole new one into it if i decide to do that?

Also can someone do a run down of which vents work on each setting

Like where should I be getting air from on max, norm, bi, vent, heater, and so on. Each setting changes which vents it blows from correct? It seems my top two front vents generate way more air than the others

 

If you hear a leak, it's probably the vac control (normally when there's a leak, the default is defrost):

https://www.thirdgen.org/forums/atta...duct010707.jpg

https://www.thirdgen.org/forums/inte...ctor-disc.html

JamesC

 

what do you mean the default is defrost?

 

The defrost will function when the other settings won't (a safeguard feature).

JamesC

 

oh, well they all work, just the side vents dont seem to put out as near as much air as the center two and when i switch settings i hear it hiss from there

Im gonna try and track down that part and see if that fixes it unless someone knows another fix

 

If you have a vac leak, perhaps the various doors aren't operating as designed.

JamesC

 

I beleive that is what is going on


Ive had no luck in finding that part in the other thread anywhere online. anyone know where to get one of these

 

I "believe" this is what you need: Valve Vac Sel GM part # 16032395. The number is good on GMPartsDirect.

JamesC

 

Yeah thats it, I found a guy selling them on ebay and he had a picture of the box listed and that same number is on it, he is ripping people off on there wanting 35 plus shipping, it costs 22 something shipped from gmpartsdirect, but I found it cheaper on amazon, Ended up paying 17 something shipped, thanks for your help man and hopefully this fixes my problem

 

camaropunk,
I couldn't find it under Amazon Automotive - what's Amazon listing as the name of this part?

Thanks, scooter500

 

Amazon?

JamesC

 

www.amazon.com Thats where I ordered it from,


scooter, the link to it is http://www.amazon.com/AC-Delco-15-71...1490096&sr=8-1

 

Well it came to day and I replaced it this morning and sad to say I still have the hissing noise, I messed with it 2 hours trying to figure it out, I tried putting petroleum on the vac lines and where they plug in and no matter what once I change the selctor hiiisssisis.......I got frustrated with it and put everything back together and gave up for now, but I did notice that my side vents put out a lot more air now.



Any other suggestions please let me know, Im thinking of getting a different control unit and trying that possiblt.

 

What a nightmare, I spent some more time trying to get this right, but still no further than before, it hisses now more than ever and sometimes doesnt quiy, ive tried petroleum to seal better but still no luck, what a head ache

 

And this is why I get closer and closer to doing an A/C and Heat delete on my car. I have windows and I have a jacket. :P

Maybe there's a way to convert all of this to an electromechanical system using solenoids? The world may never know.

 

This is the most difficult thing on my car, why wont it quit leaking?

 

Mine makes noise too. But it still switches between all of the settings well. As it is, the heater door is stuck (stuck on the A/C/Vent side), and there's no A/C. So the only thing I use is vent.

 

You can 'rent' the brake bleeder/vacuum tester, mityvac is one brand name, from Autozone and use it to check for vacuum leaks. With the heater control out, or exposed, connect it to the vacuum source for the switch and pump it up. See whether the switch itself is leaking or which setting causes it to lose vacuum.

A little hissing is normal, it can be the sound of the actuators moving. You'll know for sure it's leaking and where with vacuum tester. You can also use it to check the line from the engine side.

 

there is a vacuum line going from behind the intake and it runs down through the driver side fender and under the battery to a bulb thingy. Check that for leaks.

 

Well I can hear it at the switch, so its either the switch or a bad connection right in the area, Im debating cuting the harness and attaching them individually and seeing if that solves it. I tried Cleaning and relubing each of the switches ( old and new) still no luck, its got te the plastic harness somehow unless the new switch is bad and so is the old. Im just afraid of hacking the harness and then it still doing it and wasting time plus making it harder to replace again.

 

Personally, I'd avoid that--there has to be another way to solve the problem.

JamesC

 

Thats how I feel to im just out of ideas ive spent a couple hours the past few days messing with it and vaselining the connection I just cant figure it out, I read another thread and a guy had the same problem as me and he said he did that and problem solved, If I do do it and it quits id be ecstatic, but if I dont it will suck I did it for nothing and now made things harder if I get another switch, but atleast I can rule that out and I could always get a harness from a junk yard and get some heatshrink to reconnect it. It kinda seems like my only option right now

by the way james I enjoy reading your advice on this thread and other ones, A lot of the things you have said have really contributed to things on my car, just though id let you know.

 

Well I cut the harness and then zip tied them individually, It no longer constantly hisses, I hear it hiss and a vent open in the dash and it stops all in a couple secs. guess this is as good as it gets. Ive got another vaccum control switch being sent from a friend and I will try it but if it doesnt do any better im done with this as long as my a/c and heater are working corectly minus a hiss. I hate this design.

 

Jumping over from the other 'low mpg' topic.

Any vacuum driven HVAC system I have ever had has hissed a little bit and then clunked when the switch is used because it is actually using vacuum to move the flaps inside the heater box and system.

Try running the car and then shutting it off, wait a minute, and then try to use the control. If it's working it should still hiss and then clunk even with the engine off, because it will hold vacuum. If it's leaking there will be no hiss, and also no clunk.

 

Ok, with that said I think ive got it taken care of.

 

I think I possibly got something mixed up when fixing this.

Can someone tell me which vents it blows from when using heater and which ones for vent? thinking I possibly mixed these lines around.

 

Heater blows from the floor vents. Vent from the dash, same as A/C.