Hi

We have 99 SSEI that diverts most of the air through the defrost vents and the AC is not cooling. It is the electronic type control. Putting in manual, changing the temp setting, and/or changing air flow settings does not cause the air to cool and does not divert air through the middle vents where it should be going. I've read a lot on the forum about vacuum leaks and nipples. There is good vacuum at the cannister near right front tire. If it was cooling, I'd suspect a vacuum problem inside, but with no cooling, I'm not sure. I've taken it to a local mechanic that said the controller/programmer needs to be replaced, but he'* not certain and I can't locate a used one. Any advice would be much appreciated.

Thanks in advance,
Marion Davis, Jr.

Hmmm....two problems at the same time makes things more difficult. As you have probably read, air coming out of defrost (or other) vents is directly vacuum controlled (through the electronics of the HVAC programmer, though) while the airmix door for temperature blend is directly controlled electronically (no vacuum involved).

How the two interact together (or direct each other) may be the key to determining your issue, but you may indeed have a programmer problem or, I suppose, it could be in the control unit on the dash.

I know I will need to do some further research to help guide you on this one. Hang in there and keep checking while others put their two cents in here.

EDIT: oh, BTW, wlecome to BC

OK, after giving this some more thought, I have had both of the problems you are experiencing, just not at the same time. When I had no cold air and the actuator gear was broken, I could still command which vents for the air to come out of. When I couldn't control airflow out of the vents, I still had A/C and heat. So, I am specualting that the two can operate independantly of each other and the issue could be the programmer or control unit.

Is the A/C compressor cycling/engaging when you command A/C?

Where are you located at? It would be a bonus if someone is nearby with a used, available programmer or control unit to swap in before you buy anything new. I heard new programmers can be $300-$400 and I am sure we can do better than that, somehow.

Thanks so much for weighing in on this problem, Echo. I have to add that I cannot say that both problems occurred at the same time, so there is a chance that I may have two separate fixes that need to be done. It just seems too much of a coincidence to have these two problems occur at the same time or very close together. The mechanic is looking for a used programmer for me and still has the car. A new one costs over $600.00 from the dealer and we're going to avoid going new unless we just can find a used one, especially if we cannot know for sure that a new programmer will correct the problem. I can go up and check to see if the compressor clutch is engaging when the air is turned on and let you know. We are located in SC. Thank you again for your input on this- I've heard you're the best. Thanks as well for the welcome to the board.

Marion

I'm not sure if the '99 is the same, but I know the earlier cars had a vacuum hose that goes into the firewall a bit to the left of the master brake cylinder. If this line came loose, it would default to just blowing out the defroster.

Have you searched for information on the programmer? There is an extended write up on how to check the vacuum fittings going to it, and repair that could be quite helpful. If a new programmer is in fact needed, check by sending a PM to BillBoost37 to see if he has one.

This is a well written article by SSE Motorhead regarding the programmer and air mix actuator.

http://www.trialsnuts.com/ecc.pdf

We definitely need to try to diagnose this one carefully, as I would hate to see you invest in a programmer or any other part without investigating and testing the usual causes for each problem. And if it turns out to be the programmer or control unit, then it would sure be great if someone here had one or both that you could borrow for testing purposes or at least if someone already had a used unit they are willing to sell.

I went to the shop to check AC but the mechanic had it locked up inside. If I called him, he'd let me in to get it, but I know how I don't want to be bothered with work stuff on the weekends and since it'* supposed to be 27 degrees here tonight, we're in no hurry for an AC fix anyway. I did check the AC fuse and found it good before I took it in. I believe if the compressor was locked out due to low freon, the mechanic would have caught it. This is a family run business and the father of these guys has been at it for 30 years plus, so I have quite a bit of confidence in them. If the compressor was not coming on for the usual reasons, I believe they would have picked up on it. I realize that the suggestions anyone makes on the board may not fix the problem. I just appreciate the help and advice. SSE Motorhead did a great job with the instructions, and I may refer to these later. For now, is there a diagnostic procedure for helping to pin point the cause of the problem? Is there any way to determine if the controller or programmer is in fact the problem before I replace them? My mechanic believes it'* the programmer, and you seem to be leaning in that direction. If there'* nothing else to check, I'll likely just go ahead and get a programmer. If it doesn't fix it, I'll go from there. Thanks for the advice!

Marion

Yes, there is something else to check, other than the programmer. Reread the first paragraph of my post.

Here'* a post that goes into a bit more detail.
http://www.bonnevilleclub.com/forum/...6899&highlight

If you are able to work under the dash to check for vacuum there, I can help.I've been under the 98'* dash and the vacuum black tube from the engine compartment comes through next to the right side of the car. It connects to the violet tube which goes to the programmer. It can be pulled apart there at the connection of black and violet with a sharp tug.

If vacuum exists when motor is running or for about 15 seconds after, then I could suspect the programmer is not switching the vacuum to the one vacuum motor line that pulls the vane closed where air goes on up and out the defroster vents.

Myself I would check to be sure that vane'* motor is working. I did iton my own car by taking off a line from an adjacent motor and connecting it to the motor for the AC vane closing operation and setting the dash switch to a position that sent vacuum to the tube fro the other motor which is now on the AC motor. It worked. So I knew the motor and vane weren't broken or jammed.

I am assuming you have the dual automatic temperature control system so your programmer is easily taken off with two screws holding it to the corner of the heater box, removing the large power connection with about 30 wires to it, removing a metal rod from the temperature vane (snaps out of white nylon holder), and the little two wire connector on top of the programmer that connects to the actuator motor that'* on top of the heater box for the passenger temperature adjustment.

I did the bypass of the vacuum connector that'* slipped/hooked into the corner of the programmer box. The top of the box unsnaps easily. This rubbery plastic has little black nipples that suck closed under vacuum. The ones for the AC vents seem to do it first and worst. I cut tubes off at the 7 vacuum line attachment after writing down which colors inside the programmer matched which color coming out of the nipple connector. I Slipped 1 inch pieces of 1/8 inch internal diameter NAPA gas line rubber hose over the outside using a little water on the vacuum lines to slip them in. Replace programmer. Reconnect everything. Voila. Everything works.

If you are interested in trying this or your repair shop will do it, I have pictures and sources that might help. A junkyard had a 1995 equivalent for $100 when I checked.

I believe your lack of cold may be from something else.

Thanks, Archon

I looked for this line before and could not find anything near the brake booster. I remember seeing the post and was really hoping to find the problem there but there was nothing there that looked like a vacuum line and what was there was tight. Thanks again for the suggestion.

Marion

Imidazol,


I did a lot of reading here prior to posting and appreciate the large volume of information others have posted about this problem. Based on information I found, I removed a plastic cover under the dash and saw the multicolored lines that looked to be in really good shape.I checked the vacuum at the cannister and got about 12 inches while the motor was running. I also pulled a vacuum on the other side of the tubing and it held. From the posting I'd read here, the next step was to use a socket to remove 2 nuts, but I did not have anything deep enough to remove the nuts. They are located at the base of what looks like a long stud. I read where somebody broke something trying to get in there. If I was sure the problem was on the other side and that removing the nuts would get me to the source of the problem, I'd have gone out and gotten something to take it off, but at that point, I was not sure if I was barking up the right tree and opted to take it in to get the opinion of someone with far more experience and knowledge than me. I just reread your post and if I understand correctly, I can check without removing the nuts by swapping tubing. I need to try that before I order the controller since you may be right in saying that the air direction problem and the AC problem may be two different problems that are not connected. I'll reread your post and see which lines I need to swap.

Thanks!
Marion