Bonneville blower AC climate control problem

Hey guys I had to re-register my name because it wouldnt send me my password. Anyways whats up its been a while since I was last here. I have a 1994 Bonneville SSE with 206,000. The air from the vents seems to be pretty scarce. Sometimes, and this has only happened when I was on the highway, the air will pretty much shut off, although I hear the fan blower at high speed... I read through the other forums on this kind of issue and I have no idea what route to take. I have already done the core cleaning as told so in one of the other forums, lol the one thing I wasnt told was that when I use the hose to rinse it off that it was all going to end up with a lake in my car!!! haha Anyways that didnt work and I am almost out of ideas... Oh yea when I am driving on the highway, and when the airflow does get scarcer and scarcer all I have to do is hit ECON and wait for the AC compressor to shut off, and then hit AUTO again to get the compressor running again and the air will come out stronger again... but nowhere NEAR what it should be. AHHH I think I should just get rid of the car toooooo many damn problems!

It sounds like you have a broken or disconnected vacuum line. The air diverters are controled by a vacuum source and will default to the windshield vents in the event of a vacuum loss. You have a little tank on the firewall next to the master cylinder that holds vacuum pressure during different running conditions.

Because you can still hear the blower running at the same speed, it's still running... just now blowing out the dash vents. Check the line at the tank on the firewall.

all right, I checked and double checked the vacuum lines and I couldnt find any leaks at all. I did replace those lines earlier this year though. I did have this problem last year. I dont see how a leak in the vacuum line would cause the problem, only because once I hit ECON and then hit AUTO again the air blows a little harder ya know... is there any sensor that could be shot??? Im like out of ideas here lol... do you have any other ideas randman? Thanks for your help too!

Well, that's the most common problem and area. Can you verify my theory? That the air is being directed to the windshield vents rather than the dash vents?

The other place where there could be a vacuum problem is right at the HVAC programmer.

http://img.photobucket.com/albums/v155/randman1/Parts/DSC01710.jpg

Here's the programmer. The purple line is the source and the other colors go to the diverters. I've heard of the "connector" where the lines enter the programmer softens and partally blocks the vacuum from doing it's thing correctly. I've only heard of this twice. All other times have been the line at the tank.

Do you happen to have a vacuum gauge??

hmm... maybe I will just replace the line again for the hell of it..., but also to answer the other question, it goes out the mid-level vents too, I can choose windshield and it will go to windshield, I can choose mid-level and it will go there so that part is working fine... maybe it is because I punctured one of the vacuum lines... it is definitly possible! I will check that tomorrow or sometime this week. Just another question where is the programmer located??? Thanks so much for your help again! There are some damn nice people here!

I'll try to explain it:

A vacuum source to the purple line is dristributed to the air diverters through solenoids (silver relay looking things in the pic). As long as you have an adequate vacuum source, the diverters are are held open by the vacuum pressure. If there is a vacuum loss, which I think is what your problem is, air flow will be diverted to the windshield vents by default because of the design of the system. The tank is there to retain a steady vacuum pressure as there are changes to the vacuum in the intake manifold as you drive.

Since you already cleaned the evap core, this is the most likely cause.

Sometimes, and this has only happened when I was on the highway, the air will pretty much shut off, although I hear the fan blower at high speed...

At this point, feel if the air is coming out the windshield vents.


the HVAC programmer is located above the passenger's hush panel (kinda behind and below the glove box). It normally just looks like a black plastic box but the top cover was removed for the pic.

hmm I will have to try that... I will also have to check where the air flow is going when I am drivin on the highway although that wont be until thursday. I will definitly let you know what I find out! Thanks for your help!

ok the AC level lowered itself again BUT it was not coming out any other vents... do you have any other suggestions?

Here's what can cause your problem:
Blocked EVAP core - you already cleaned that
Air flow directed to non-selected vents - you say that air is not directed anywhere it shouldnt be
Blower Control Module failure - you would hear the blower change speeds or would not work at all
Blower motor not working properly - same as above

I feel very strongly that you either have a simple vacuum leak or your blower motor is on it's way out.

Is it possible that the fan itself is loose on the hub? You would lose air flow but still hear the blower motor turning. Just grasping at straws :)

well im just confused because it really really sounds like the blower is going at full speed when it does this... well its not real good in the first place BUT when it decreases to almost nothing the blower fan sounds like its going strong at full speed, once I hit ECON and let it shut the ac compressor off and then hit AUTO again it comes back out heavier again... maybe it is a vacuum leak BUT I dont understand why its doing what its doing... and it ONLY does it when I am at a constant speed of 55 or higher, I can have the AC on for like 2 hours driving at 35mph but once im on the highway about 20mins later it slows itself down... but like I said the fan is at full speed!!! wow im hell of a confused!

and I dont THINK it does this when the heat is on

I'm not sure what else to tell you other than you're probably going to have to test some things out. Get yourself a volt meter and a vacuum gauge and dive in.

It would be very odd that you experience this problem with the AC but not the heat.

I know right? Trust me lol I bought this car with 175000 out of an auction two years ago, it was a POS, a RUSTBUCKET!!! Now there is not one bit of rust, almost new interior and basically the whole car was rebuilt by me... Ive come across some of the most F'D up problems it is unbelieveable... This is yet just another chapter out of a book.

Ok well I have an idea, it is a longshot but if it works I will let you know. I will try it within the next few days.

Whatcha got in mind?

Hey guess what I have a new thing to add to this! Randman I hope you are still here because uve been a big ass help. ok like you said before well... asked before if the air was going to a different loacation such as the windshield... well driving home from work today I noticed that when the RPM's went UP the air wend DOWWWNNNN... welll I did it again and again and again and I was laughing my ass off because I figured my car was figuring out a way to make me not speed anymore :-) anyways... I put my hand up to the windshield next time the light turned green and sure enough gradually the air went DOWN on the mid-level and went up to the windshield... I couldnt believe it! Ok so I re-read this thread and you said that it could be because of a broken or disconnected vacuum line... could it be because of the vacuum tank that the lines run to? Oh and ALSO it was only while it was in gear... not in Neutral or park... I dont know if that makes a difference. Let me know what you think! Thanks a lot

The vacuum tank or the line(s) going to/from it are the most common problem area. There should only be one vacuum line that plugs into the tank but there is a T shortly down the line. There's also a check valve which allows the tank to "store" the pressure.

More often than not, people in your situation will find the line going to the tank disconnected or leaking. Your check valve may be in backwards because I think I remember you saying that you changed some lines at some point.

You might want to invest in a vacuum gauge. This can be helpful to pinpoint where the problem lies in the vac system. they're less than $20

http://www.autozone.com/images/products/acm/acmcp7803003.jpg

I will most likely get the gauge. It will be a while because our weather here is jumping from 90-50 from rainy to sunny so I dont know when Ill get the chance to do it. I will let you all know the outcome. Thanks for your help Randman!

Ok nevermind it seems when I changed the vacuum lines two weeks ago I put one that was a little too big and wanst making a secure line so it was leaking... LOL so not im left with the original problem with not enough air coming out of the vents I THINK I AM GOING TO GIVE UP!

So after you replaced the vacuum line, the air flow was decreased?

no, it was still the same, it didnt really increase when I changed the vacuum line, but the problem with the air flow going to the windshield stopped...

Is the evap core freezing up when a/c is on thereby restricting air flow across evap? Grasping at straws here.

Forget what I posted, I just realized there are two pages here, didn't read the thread all the way through. Sorry, my bad.

I am having siomilar problems but have not done the evap core cleaning yet, I am having trouble locating it, I have a 92 bonne ssei and I have looked behind the fuse bank under the hood, a location I have read about in this forum, Any hints or pics would be very helpful.

The Blower Control Module under the Maxifuse/relay center under the hood more towards the passenger's side. You can also follow the wire loom from the blower motor right to it. Remove the BCM to inspect the evap core and clean (vacuum) if necessary.

I think that I am having a very similar problem with my 94 SSE. It is if the deflector doors get stuck. If you cycle the heat from 60 to 90,shut it off, go from ac to econ, etc. you eventually get the ac to blow some cold air. Same issue now that the weather is cooler, the heat wants to come out of the vents at a lower temperature.
Any ideas here?

Vacuum sources do not control the temp, only the direction of air flow. I'd suspect a failing air mix actuator especially if the temp display blinks on your ECC head. Do a search for "air mix actuator" in this forum. There are many threads that address the problem

Well for my car all I have to do is turn it off then turn it back on and the air will come out at a better speed, nowhere near what it should be, hell my friend has a 92 Cavilier and the air nearly pushes my head back!!! This a 30 something thousand dollar car and believe me the air sucks!!! Ive tried everything and this board has helped but im starting to think maybe it is my blower motor, it sounds like its a full speed but hell the cars old, 208k!!! Cant complain if shes still runnin

Im having aproblem also with Climate Control and its killing me.I spent 2 days going over vaccuum hoses which i did find a leak by throttle body and fixed.Cleaned out heater core and changed hoses its ok, changed thermostat,cleaned out evap core,fan woks well ,but only coming out of floor or defrost on heat,blowing warmish cool air.When on A/C it will come out of mid vents.Top rad hose is hot,outside air temp seems normal.spent hours on Hvac programmer che cking leaks,(the for resistor looking things in HVAC programmer that have brownish filter on on them 3out of the4 when I cover with finger make a air noise ,dont know if means anything.
1990 bonn sse ,digital climate control,3800

please ,please help I cant take it JDQ and thankyou

Im having aproblem also with Climate Control and its killing me.I spent 2 days going over vaccuum hoses which i did find a leak by throttle body and fixed.Cleaned out heater core and changed hoses its ok, changed thermostat,cleaned out evap core,fan woks well ,but only coming out of floor or defrost on heat,blowing warmish cool air.When on A/C it will come out of mid vents.Top rad hose is hot,outside air temp seems normal.spent hours on Hvac programmer che cking leaks,(the for resistor looking things in HVAC programmer that have brownish filter on on them 3out of the4 when I cover with finger make a air noise ,dont know if means anything.
1990 bonn sse ,digital climate control,3800

please ,please help I cant take it JDQ and thankyou

Forgot to mention I can see acuator arm is in good shape and moves 90 degrees closing and opening door does that mean I can eliminate Hvac leaks. thanx JDQ

Forgot to mention I can see acuator arm is in good shape and moves 90 degrees closing and opening door does that mean I can eliminate Hvac leaks. thanx JDQ

my car has no heat and i kind of have similar problems. my problem is the heat isn't coming out of the vents and the line is warm. where is the door flapper to the heater located?

my car has no heat and i kind of have similar problems. my problem is the heat isn't coming out of the vents and the line is warm. where is the door flapper to the heater located?
tHE DOOR FLAPPER (ACTUATOR)is behind glove comp.Take couple screws out of hush panel under glove box to lower down ,take 4 screws out of glove box to take it off and voila ,you will see different color small hoses going to Hvac programmer ,take off and check for any leaks in these vaccuum lines,also check vaccuum lines under hood first they tend to get soft or crack at rubber connectors.Anyways up above Hvac programmer on top of air vent molding you will see a metal bar and that is attached to your flapper door.Turn heat on lower temp for air and see if this metal arm moves back and forth with no hesitation or obstruction.Also right behind that vent molding (2 screws) is your heater core.Im assuming you have digital climate control.

tHE DOOR FLAPPER (ACTUATOR)is behind glove comp.Take couple screws out of hush panel under glove box to lower down ,take 4 screws out of glove box to take it off and voila ,you will see different color small hoses going to Hvac programmer ,take off and check for any leaks in these vaccuum lines,also check vaccuum lines under hood first they tend to get soft or crack at rubber connectors.Anyways up above Hvac programmer on top of air vent molding you will see a metal bar and that is attached to your flapper door.Turn heat on lower temp for air and see if this metal arm moves back and forth with no hesitation or obstruction.Also right behind that vent molding (2 screws) is your heater core.Im assuming you have digital climate control.
Also check and maybe clean your evaporator,possible blocking blower air.Is your top rad hose hot?

I just got done fixing a similar problem. I had a lead given to me, however, in that a GM mechanic told me that a high failure rate in 97's with air direction problems came from where the vacuum harness connects to the HVAC Programmer. (Careful checking on this because I would image that if you don't have a problem here, you might have one after trying to remove the white vacuum harness connector from the HVAC programmer black connector, particularly if the auto is old and been subjected to a lot of heat.)

Regardless, my symptoms were with a full roaring fan at high speed that a slight amount of air came out the windshield and no other vents. I removed the glove compartment and the shield under it (HEY! WATCH THAT AIRBAG CONNECTOR!!! DON'T UNPLUG IT OR ALLOW IT TO SEPARATE IF YOU TRY TO REMOVE IT!!!! THE ONLY WAY TO DETACH IT FROM THE PANEL IS TO PUSH THE LITTLE GRAY NIPPLE BACK UP THROUGH THE SOUND BOARD COVER THAT YOU ARE TRYING TO REMOVE.) I removed the vacuum from the orange tube that was splicing the purple vacuum source line (located before it goes into the harness and into the HVAC Programmer). The source vacuum (with engine running ;-)) into the harness from the vacuum tank tested great (put line up to finger and felt a sharp pulling of skin into the line at which point the engine idle smoothed out - alternate test, check here for 15 inches of vacuum :-).

However I couldn't get the individual lines out of the white harness connector to individually check them (they are probably not supposed to come out). I also could not seem to get the white connector off of the programmer after removing the single attachment nut. The GM mechanic had told me to check this connector for problem "nipples" and sure enough after forcing off the white vacuum harness connector from the HVAC Programmer, I found one of the "nipples" broken.

At that point I was not sure if I broke it when force-removing the harness or if it was broken to begin with, and thus causing my problem. I finally found a tube to use to use my mouth to suck on each one of the vacuum lines. In each instance I heard the actuator move and there was no leak. (This is probably not the approved method of testing :-). I had to make a decision at this point, look for a used programmer at a junkyard or take a chance that this "nipple" was broken before hand. (I was reluctant to pay the $1000 the dealer quoted.)

Before removing the programmer I had observed that the actuator motor on the bottom of the programmer had appeared to be functioning correctly, as were all the numeric indicators from the dash control pannel. I saw the motorized actuator slider move from left to right after I turned the temperature control from 68 to 98. At this point, since "most" of the HVAC programmer's functions appeared to be responding as I would expect, I decided that the HVAC programmer was likely OK and hopefully that the broken "nipple" on the unit occurred before I pried off the harness. I needed to jumper around the (at least for now) broken connector block. (From experience I also know that a break in any vacuum circuit will most of the time cause the whole vacuum system to fail.)

I racked my brain, knowing past difficulties of finding vacuum tubing, but something hit me and on a Sunday I drove down to PetSmart where I picked up a $1.75 roll of TopFin 6' MINI (key word) airline tubing (in the fish aquarium side). I cut the vacuum lines going into both the connectors, those going into the white harness and the programmer black connector (carefull, some of the lines change color; write down what color goes in which side of the connector). The mini airline was perfect for sliding over both sides of the vacuum line to splice them and when I re-installed the HVAC Programmer, the A/C worked perfectly. :-)

Just performed this connector bypass procedure on my 96 ssei and it works great. Thanks for the help from everyone in this thread

This method of repairing the HVAC programmer is excellent. Used programmers are very likely to have or to develop the same problem during removal and reinstallation (degraded/leaking connector bodies) and are expensive. New programmers are currently $636.00! Use vinyl, not silicone, aquarium airline. Cut the vacuum lines close to the connector and, using one-inch sections of air line, butt the lines together in each splice to preserve the stiffness of the vacuum lines.

This method of repairing the HVAC programmer is excellent. Used programmers are very likely to have or to develop the same problem during removal and reinstallation (degraded/leaking connector bodies) and are expensive. New programmers are currently $636.00! Use vinyl, not silicone, aquarium airline. Cut the vacuum lines close to the connector and, using one-inch sections of air line, butt the lines together in each splice to preserve the stiffness of the vacuum lines. Welcome to AF and we appreciate your input; however, this thread is 3-years old and our guidelines limit posting in threads over 3-months old.



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