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The 1/8 tubing simply pushes on the nipples on the programmer-
I would give yourself a liberal amount of tubing, giving you the
room to connect it while you are not upside down under there.
(though I used 7/64 ID tubing mentioned in post 14) I also labeled the tubing with the corresponding original color to make installation easier while under the dash.
I don't know if outside temps have as much to do with it, as perhaps the overall care and maintenance of the car.
I can see where maybe parked outside in the sun all day might have some effect on it though.
Trust me, it gets over 100°F here in Missouri too during the summer.
But my car is parked in a garage, and not out in the sun everyday.
I do drive it to work 3 or 4 times a month and it sits outside then.
I had this problem. Mine was originally a Texas car & the interior was baked - so maybe it is related to interior heat. I don't believe there is any "care and maintenance" that could prevent it from happening. It was just a poor decision to change the connector material in '96.
I want to thank everyone for their advice on this subject matter. My son and I worked on my car this weekend. I am an engineering manager and I have to tell you who ever designed this, and then approved the design should be fired. What a failure design and inadequate interface. We took the seat out for easy access and since my son is thinner and more flexible than me he did the under the dash work. The nipples on the three of the vacuum lines were clogged and four had partially collapsed nipples. I experimented with the two nipples in the header that had no vacuum connections and tried putting inserts into them so they wouldn’t collapse in the future. I used some straws on air cans. The only problem was the material for the nipples was so soft that inserting the straws in would scratch the interior surface and left a potential clog.
So I trimmed back the ends on all the nipples about 1/16 of an inch so they would not close on themselves. When reassembling we got rid of the press nut and put a self locking 7mm nut in its place. I believe this lock washer in part contributed to the problem because it loosened up over time and allowed debris to get sucked in where the vacuum headers interfaced. I also added a thin coat of vacuum grease to the outside of all the nipples to make a better seal. We put it all back together and it worked perfect. Now I don’t know if this will be the final solution and I may need to go back in the future with a more radical solution such as splicing the vacuum lines together permanently. For now it works perfect and I have true climate control and all the buttons are instantaneous. Much needed in the current 105 temps in Tucson. Again, thanks to all for your advice.
In addition to the two fixes above, I can confirm another solution that worked for me. I disassembled the vacuum connector and cut the soft rubber tips off the vacuum plugs. The module was reinstalled in the car using a longer bolt, lock nut, and a standard nut to secure the vacuum connector to the module. So far everything works as it's supposed to (knock on wood).
Ok, I have a new wrinkle on the controller. 96 Collector Edition. Several years ago I took mine out and clipped the nipples, greased them and put a lock nut on the connector. Worked fine. Now, the light on the buttons on the controller flash after I start the car. I get a code on the A/C computer that the Temperature doors have a circuit fault, but it seems that the real problem is that the A/C controller is not restoring the logic in the system when I start the car. Sometimes the Air works fine out of the correct vents and then suddenly I get full heat out of the vents. Sometimes when I press the AUTO button, it defaults back to "75 degrees" and "0" fan speed. Is this the programmer causing this problem? For some reason is the programmer not getting the logic restored? Anyone else had this problem and/or fixed it?
Last edited by jad9943; Oct 13, 2012 at 08:07 PM.
Reason: Adding Car info
Digging up an old thread.. I know.. but just used it and fixed my problem
I ended up just removing the whole connector unit and running 3/32" ID tubing thru the holes. 8" is just about perfect and lets the controller dangle while you're installing the wires you cut off on the existing connectors. Remember to use a little WD-40 to make it easier to slip the tubing over. I got all my tubes in the 3/32" about 1/4" deep..
Digging up an old thread.. I know.. but just used it and fixed my problem
I ended up just removing the whole connector unit and running 3/32" ID tubing thru the holes. 8" is just about perfect and lets the controller dangle while you're installing the wires you cut off on the existing connectors. Remember to use a little WD-40 to make it easier to slip the tubing over. I got all my tubes in the 3/32" about 1/4" deep..
lol.. of course not.. I always forget to do that.. Its very simple though.. I will take a picture of the part I completely removed.. You don't need it..
I purchased a 6' piece of 3/32" id tubing from napa auto and cut it into 5 equal lengths. marked the colors with tape.
As previous poster mentioned, when you get your head up in the dash. (I removed the kick panel and the seat) You will see a cluster of 5 coloured vac hoses (shown in pics). Cut those right off at the connector, as close as you can and remove the big black box.
The back of the unit is held on by a piece of cardboard and tape, take that off, remove the green rubber connector, take off the screw in the middle and just connect your new vacuum tubing directly to the 5 hoses on the inside. All your basically doing is deleting the factory quick connect.
The 3/32" vacuum line from napa squeezes perfectly through the holes in the programmer box. Make sure you put some wd-40 so you can get the existing vacuum lines in. (I got about 1/4" deep). Now you will have the black programmer box in your hand, with 5 8" tubes dangling, replace the controller in the car, and just match up the vacuum lines to the color codings you made.
The 3/32" id tubing is very snug, so I don't really think they will ever pop, maybe in another 20 years..
If my thread helped in any way, great..I took my basic info fro m someone in the Forum.
The bottom line is, if you are going to a lot of trouble, you might as well fix it permanently.
Don't forget the controller..it's job is to send the signal to the proper solenoid in the programmer. The button contacts might need cleaning.
Congratulations on a job well done.
BonAir
Heh.. mine was plugged solid.. Wouldn't even come after 20 minutes.. You could probably just cut those little rubber tips off and make sure the green rubber piece is put on solid.. But like BonAir was saying, its a royal PITA job.. may as well do it correctly..
As long as you got good quality vac tubing and make sure ID is 3/32" i am very confident they won't be popping off for a long, long time. The conditions are very ideal under the dash for them, they will get warm, but never as hot as your engine bay, and thats what they are developed for. I mean.. it doesn't take a whole lot of vac pressure to do its job.
I also just fixed the HVAC controller on my '96, although I went about it a little differently. After getting the two halves apart where they join at the controller (took awhile I must say), I cut the colored tubing at the connector where it goes to all the diverter doors and removed the controller from the car.
Undid the bolt that holds the other half of the connection on the HVAC controller. Took the header assembly out of the controller and cut the tubing at the connection block. Now, this eliminates any connection on the controller itself.
Now here's where you can save yourself lots of time on your back. Cut the colored tubing close to the connector before you even get started! Then you can remove the controller with both halves of the connection attached. If I had known I was going to do the repair the way I did, I would have definitely done this. There's no need to separate the two halves while your upside down in the car!
I used 5 pieces of 3/32 ID tubing, each cut 8 inches in length. Connected each piece of tubing to the five colored tubings coming from the header. Replaced the header in the controller and fed the new tubing directly through the holes in the controller. Marked each open end of the new tubing with the corresponding color, sprayed a little CRC in each end and placed the controller back in the car. After that, it was as simple as matching the colors to the new tubing.
No worrying about collapsing tips or matching up the two halves of the connection and then trying to make sure it's tight enough. Yes, the A/C now comes through the vents and I no longer have icicles on my windshield.
Another word to the wise... Remove your driver's seat. It's easier on the back, but a little tough to get out of the car. Make sure someone's within yelling distance!
LT4DH8R (and others) Thank you. After receiving estimates between $800 and $1400 to fix the lazy AC center vent, and hearing the various horror storied associated correcting this condition I read your post (and others). I followed your suggested repair procedure (albeit I used 7/64 tubing instead of 3/32) and I now have instantaneous response to all HVAC control buttons. This fourm, actually the members are awesome and again Thank you all. If anyone in or near Atlanta needs help with this repair please give me a shout. At least now I'll have AC on the way to the Chiropractor.
Bill
Having read all the threads on this problem I was having the same trouble in my 93. This is supposed to be only in 96s. I bought a new programmer for a 93 and had it installed. When I looked at the programmer taken out it was the one for the 96. Whoever did the repair substituted a newer programmer thinking it would work and be better. Wrong. I now have no problems with the HVAC and it works likes it is supposed to. If anyone needs a programmer for a 96 pm me.
Cliff Harris pointed me to this thread. Thanks to all who posted their experiences and advice. I bought my 96 Base Coupe from Wathen1955 last March. He took great care of it and told me about the slow action of the A/C programmer/controller. I decided to tackle the repair this weekend and felt well prepared.
My experience was good, although I have a new appreciation for the term "Corvette Yoga". The complete project took me about 5 hours, including prep work like removing the driver's seat and roof and the dash under cover.
Removing the A/C controller module was a challenge. The one 7mm screw that holds it in is easy to remove. The limiting factor was the shortness of the colored vacuum lines from the module to the servos. Don't bother trying to unplug the electrical - it has plenty of slack and will allow the module to drop all the way to the floor. After re-reading this thread, I decided just to clip the colored vacuum lines as close to the plug as I could. Since the plug is the problem anyway, vacuum lines can be easily spliced.
Once I cut the colored vacuum lines, the module dropped out readily. Getting the module on the bench, pulling the push-on nut, the problem was immediately obvious. The #4 nipple - vacuum source - was so poorly manufactured, there was basically no hole there. I trimmed about 1mm off the nipple, then another, then cut down to the bulge where it seals against the plug. It was almost completely closed up.
I just decided to bypass the whole connection assembly and use 5/32" rubber vacuum line. The colored nylon lines push into the rubber pretty snugly. Just spritz on some soapy water and insert a 1/4" or so.
I bought 6' of rubber line for about $2. I cut 12" sections and marked the line with tape for each color. Install the lines on the servo feeds and vacuum source under the dash first. That involves some "yoga". I held the servo feeds with a pair of flat pliers and twisted the rubber onto the colored nylon about 1/4".
In the module, remove the nipple array at the corner, cut the colored lines at the round array, and drill out 5 of the holes to 1/4". Then inside the car just feed each line into a hole in the module box and connect to the corresponding color inside the module. Then just reinstall the box above the accelerator.
My AC controller works flawlessly! It will respond to any change command in 2-3 seconds.
Thanks again for all your experience. This was the most difficult car repair I've attempted in 30 years, and it went really well. [ATTACH]Attachment 47866409[/ATTACH]
Last edited by Dad3Sons; Mar 2, 2015 at 12:15 AM.
Reason: add photos
Figured I would post my pictures but the previous post is what helped me solve the issue. This is an ancient post but I'm sure others will need this info as I did. Module is relatively easy to remove. Reinstall is not so much fun. Also, I checked the connection & check valve under the fuel rail cover before diving into this.
As you may be able to see in the pictures-
1)I left the vacuum harness from the HVAC controls intact. That way if someone ever purchased a new module & wanted to plug it in as original they could do so. I used weed eater fuel line, which is hard plastic (purchased @ O'Reilly). I stuck the weed eater fuel line, approx. 2 inch pieces, into the original harness.
2)The module only has a cardboard backing so it's simple to access the internals. I removed the vacuum junction block from the module & then cut the vacuum lines from the block.
3)I then attached very small diameter rubber vacuum hose to each of the lines. The hoses I installed were about 6-8 inches long. I installed tape on each hose with the color written on the tape. Thought about using magic markers to color the tape the correct colors but didn't.
4)I had to use a dremmel tool to cut the portion of the module where the vacuum block fit in the module to feed the vacuum lines through. Could simply drill some holes in the side to feed the lines through also.
5)This part sucks unless you have infant sized hands, really long arms, great strength & a gymnast background. Thank goodness the GM engineers left a solid 2 inches of slack in the vacuum harness from the HVAC controls. The wiring harness has plenty of slack but not the vacuum harness. Once I got ahold to the vacuum harness I attached the correct labeled vacuum hoses to the harness, which had the weed eater fuel line sticking out of it. Not allot of working room under there. Where I was able to get ahold of the vacuum harness to attach the hoses, the hoses wrap around the wiring harness once you reinstall the module. Has no affect on the operation of the module. Vent, floor, defrost etc. all work perfect now. No delays in switching modes. Hopefully the pictures will help someone else with this too.
You'll find it sooooooooo nice when the A/C blows cold out the front vents "on demand"!!! Congrats on the fix!!
Joe C in NoCal
Originally Posted by hgpreston
Figured I would post my pictures but the previous post is what helped me solve the issue. This is an ancient post but I'm sure others will need this info as I did. Module is relatively easy to remove. Reinstall is not so much fun. Also, I checked the connection & check valve under the fuel rail cover before diving into this.
As you may be able to see in the pictures-
1)I left the vacuum harness from the HVAC controls intact. That way if someone ever purchased a new module & wanted to plug it in as original they could do so. I used weed eater fuel line, which is hard plastic (purchased @ O'Reilly). I stuck the weed eater fuel line, approx. 2 inch pieces, into the original harness.
2)The module only has a cardboard backing so it's simple to access the internals. I removed the vacuum junction block from the module & then cut the vacuum lines from the block.
3)I then attached very small diameter rubber vacuum hose to each of the lines. The hoses I installed were about 6-8 inches long. I installed tape on each hose with the color written on the tape. Thought about using magic markers to color the tape the correct colors but didn't.
4)I had to use a dremmel tool to cut the portion of the module where the vacuum block fit in the module to feed the vacuum lines through. Could simply drill some holes in the side to feed the lines through also.
5)This part sucks unless you have infant sized hands, really long arms, great strength & a gymnast background. Thank goodness the GM engineers left a solid 2 inches of slack in the vacuum harness from the HVAC controls. The wiring harness has plenty of slack but not the vacuum harness. Once I got ahold to the vacuum harness I attached the correct labeled vacuum hoses to the harness, which had the weed eater fuel line sticking out of it. Not allot of working room under there. Where I was able to get ahold of the vacuum harness to attach the hoses, the hoses wrap around the wiring harness once you reinstall the module. Has no affect on the operation of the module. Vent, floor, defrost etc. all work perfect now. No delays in switching modes. Hopefully the pictures will help someone else with this too.
(though I used 7/64 ID tubing mentioned in post 14) I also labeled the tubing with the corresponding original color to make installation easier while under the dash.
