richauto

You may want to check the vacuum storage canister located under the hood in front of the l/f wheel. I have a '94 ,the vacuum connection was broken there good luck

Silver96ce

I have a '96 and had two problems with the HVAC system when I purchased it.

First, the head unit in the dash did not always respond when I pressed a button. There are threads on the forum explaining to take it out and carefully take it apart. Then you use a pencil eraser to clean the button contacts on the unit board. Also I used an electronics spray cleaner to spray off the contacts and connectors after using the eraser. This fixed the headunit.

Second, for the vents not blowing, it is the programmer on the firewall above the gas pedal that is causing the problem. If you do a search, you will find the threads dealing with the problem. The main problem is the 1996 programmer was a one year deal with soft nipples on the connector block coming out of the programmer itself. I fixed mine but I did not take pictures. If you are willing to do some work and physical contortions, you can fix it for around $15.00. I took out my drivers seat, removed the hush panel and then the metal panel above it. You may also want to remove the sill cover and the speaker in the drivers side footwell for more room. Then get on your back with your legs in the hatch and your head under the dash. Look above the gas pedal and on the firewall is the programmer. The connector for the vacuum lines is attached with a press on nut in the middle of the colored lines. Some people pry it out but I used a long reach needle nose pliers and pulled the whole semi-clear rubber connector off pretty easily. Next remove on small bolt on the bottom and slide the programmer down. Then remove the locking tabs on the top connector and remove the top connector. To fix it some people trim the soft nipples and reattached with a locknut. I skipped it completely and removed the bolt and connector from the inside of the programmer. I got five feet of 7/64 vacuum line from NAPA and cut into five equal lengths, attached to the nipple in the programmer, drilled out the holes to a size that allowed me to slide the hose through the old connector. I also used 1/8 vacuum caps on the unused nipples in the programmer (may not be necessary). Then label the lines with painters tape for the right color vacuum line and insert a hard 1/8 vacuum connector into each vacuum line. Get back under the dash, plug the hard connectors into the corresponding color vacuum line on the semi-clear connector and reverse the rest of the installation.

If you do these two fixes, the HVAC system should work fine. Good Luck.

bradleyj

Well, I finally got a chance to begin this project! It took me a while to get the lower dash off, then I saw the unit hanging on the wall with several messy bundles of wires in the way. I managed to remove the small bolt holding it to the wall, sliding it down is much easier said than done! I had to push the unit up against the foamy wall and try to squeeze (and I mean SQUEEZE! I'm scared I'm going to crush something underneath the flimsy paper backing of this unit) it down past other stuff but of course I need to first remove the vacuum hose connector. I tried removing the clear green connector feeding all the hoses into the unit by tugging on it with pliers but it seems stuck and there's absolutely no way I can access the bolt hidden between the vacuum lines. Furthermore, it doesn't seem possible that I will ever be able to re-secure the connector in the cramped space I'm allowed.

I can do all the reading in the world on the topic, but I still feel like I need to get the unit out and touch/see for myself what is going on to be able to even begin to contemplate solutions.

So 1st, what am I doing wrong? How do I get this thing out, and will I ever be able to re-secure it?

2nd, can the car even be driven with the vacuum lines not feeding into the controller? I'm just trying to imagine worst-case-scenario.

Please reply quick, I'm very nervous about all of this.

Silver96ce

1. You need to remove the vacuum connector before you remove the small bolt holding the programmer to the firewall.
2. You need to use a pliers like this -
to remove the vacuum connector. Grab it and twist hard back and forth to remove it. It only took me a couple of seconds and then I took the small bolt off at the bottom and slid the unit down.

bradleyj

I'll reattach the bolt and see if I can yank that clear-green vacuum connector off later today. My concern though is, with it being that difficult to remove, will I have issues getting it back on?

bradleyj

Hey Lanny, I just realized I never replied to your post! I'd love to see pictures of the problem and the fix! Pictures would help me a ton with this issue.

I'm documenting my repair journey with video, hopefully once all this is done I can help future 96 owners.

lt4obsesses

I'm in for this too, I have the same exact issue. Blows cold air through the floor and defroster, but not the dash. Watching this thread...

Silver96ce

If you use the method I used (replacing the connector on the "box"), you will have no problem reconnecting the semi-clear connector. Sometimes the biggest problem in making a repair is getting over the initial fear of "what if". As the old saying goes - Just do it.

bradleyj

Thanks for the encouragement! I came home after work today all pumped up and excited, hopped under the dash, re-fastened the screw holding the box to the firewall, grabbed my big ol' needle-nose pliers and gave the connector some good tugs. No avail. I then grabbed the RoboGrips, maneuvered those into position and really tugged and wriggled the connector trying to pull it out of the a/c programmer box, still can't get it to budge. Any solutions? I feel like this is a really stupid roadblock to get stuck at :/

Silver96ce

The nut holding the connector on is a flat press-on nut. You can try prying it off with a flat bladed screwdriver or grabbing it with a needle nose pliers.

Silver96ce

As an additional thought - maybe the prior owner took off the connector before and used a regular nut to put it back on - feel in the center of the connector with your finger and see what you can find out.
I have to go out tonight but will check back later on. Good luck - sooner or later you'll get it off. In some repairs I get lucky and things go well and in others it seems that everything goes wrong but sooner or later I get it fixed. You will too.

blownrunner

Any idea where that might be on a 91 zr-1?

GonHuntin

I just did this repair on my 96 today......you may not have seen it, but there is a flat "push nut" holding the clear vacuum connector on, it looks like this:




I used a small flat bladed screw driver to pry the push nut away from the clear connector, then used needle nose pliers to yank it off the screw........the connector will then slide off the box and you can remove it.

Once you get the programmer out of the car, it is easy to see why these nipples collapse. I trimmed them down to where they start getting fat, with a razor blade. It is easier to trim them if you remove the screw holding them in the box and remove the vacuum manifold.

I trimmed the rubber nipples, replaced the screw with a longer one, put the box back under the dash, reconnected the vac. connector and used a washer and lock nut to keep the vac connector attached to the box.........it fixed the problem and now the A/C works as it should.

If you can remove the panels to access the programmer, you can fix the problem.......

pianoguy

You'll find some pics in this thead - I found it helpful a few years back:

http://forums.corvetteforum.com/c4-t...l-problem.html

Cliff Harris

Here's a link to the post in that thread that has the pictures:

http://forums.corvetteforum.com/1580705187-post33.html

The "collapsing nipple" problem only occurs on 1996 cars.

FASTAZU

Just went thru this on my 96, When I reinstalled the vacuum gang plug I used a small washer and nut. If you take out the driver seat it is much easier to get under the dash.

Good Luck with the repairs.