raid007

Used these Brass 2.5mm solution for a permanent fix.
https://www.etsy.com/listing/4945689...s-24-raw-brass
Hope it helps all future repairs !!

1Asterisk

I found this today. I’m preparing to finally pull this one off. This helped me see what I’m about to undertake a bit better.

rollin18

this is timeless..
is this fix only for the digital automatic controllers?

i have same problems but i have the manual dial control head
just for time line refrnce the world is now in the COVID-19 PANDEMIC! AND "SOCIAL DISTANCING" IS THE NORM

Clock-work

The fight to remove the vacuum hose connector made me get creative. I wasn’t going to fight with that sheet metal nut ever again. I had an aluminum pinion gear salvaged from some mechanical device that was just begging to be repurposed for this project. No more needle-nose plyers! It’s good to own a small metal lathe

Jaime-Corvette

In 5ft10 and 180 pounds. Tell me how much of a pain inthe *** it was to do a complete hose replacement for the HVAC from the firewall

Clock-work

I’m 6’ 1”, 200lbs and find it not too impossible to work under the dash if I completely remove the driver seat. One thing that helps is having someone stand by to pull you out.

1Asterisk

So today was the day. I'm 6'1" and about 205. The challenging part (as most know) is really just the lack of space. After removing the lower dash pad and panel I went for it. Once that one little 7mm bolt was out I truly realized what I was in for. You only have have inches of movement in trying to get the push nut off. This was first time doing this job. I think if I ever had to do it again I would have much better knowledge of how removing that push nut works. I couldn't really see what I was grabbing with my pliers. I intended to try a pair of needle nose vice grips. I wanted to snap them on the push nut then just twirl it off. I thought this would make it easier than trying to grab it with pliers 1000 times. After a bit of not knowing if I was getting anywhere I went with the final solution.

That meant just snipping the connector off. Doing that allowed it drop free. With a little more wiggling it came out. Now my intention to was to bypass the connector and splice the lines directly to each other. I just wanted to have it apart in hand just in case I changed my mind and went with either trimming back the connector tips or inserting brass.

Once it was out I took it inside to inspect it. Those rubber connector tips were soft and sticky. It was easy to see first hand why things were not working. I used 5/32 vacuum line and put them on while inside. I used a small piece of tape to label each by color. I use a qtip with a faint amount of WD40 on it to lube up the ends of the vacuum lines to help the 5/32 slip over. This worked well. The new line would slip on something like 1/4 to 3/8 inch before it became very difficult to do more. I tested by pulling to see how much force it would take to separate them. I was pleasantly supervised to feel they were very snug. You would really have to be stupid to accidentally pull it apart. At least I hope.

I took it to the car. Each line has an extra 18 to 20 inches of vacuum hose. My goal was to have enough to splice the lines prior to reinstalling the unit. This was difficult due to space again. Still it went well. I tested the car before reinstalling everything. It worked flawlessly! Button presses resulted in nearly instant vent switching. Last week I had taken the head unit off/apart and cleaned all the contacts. So I knew the buttons were freshened up.

I installed the unit with putting the extra vacuum line in the void above it. Everything went back in place fine. I will say that taking out the lower right bolt on the metal dash panel was quite annoying. I just couldn't reach it very well due to the middle wall of the car. Also the carpet panel is annoying to put in and out on the side with the torx screws. You can't really see the little floating nuts that they are screwing into. It wasn't that bad, and really a minor complaint. I was just ready to go for a test drive at this point.

Once it was all back to normal I drove for about an hour. With full control over my vents.

I think total time invested in this was about 2.5 hours. I think if I had snipped the connector off to start with I would have saved at least 30 to 45 minutes. I was going to take pictures, but there wasn't anything not already covered in this thread to see. The pictures above document this pretty well. Part of the reason I bypassed the connector and didn't just trim the heads back was they felt very soft and a little tacky. I think they would have continued to be a problem in the future. Now I should be trouble free.

This topic certainly was awesome. There's no way I would have attempted this without it.

raid007

1990-1996 Corvette #5 - C68 HVAC Programmer Module Removal -(2020 post)
https://www.youtube.com/watch?time_continue=2&v=3jgvX967Q0o&feat ure=emb_logo

RC4G

A couple observations and pics of my repaired controller:

• Any one successfully performing this repair WITHOUT removing the driver's seat first has no bones in their body.
• I replaced the thin cardboard backer with a spare piece of plastic packaging cut to fit as mine looked pretty sad.
• Vacuum line to number hole mapping once block is removed:
  • 1 = PINK (rear mode blend door)
  • 2 = WHITE (A/C defrost blend door)
  • 3 = blank
  • 4 = BLACK (vacuum source)
  • 5 = blank
  • 6 = BLUE (front mode blend door)
  • 7 = ORANGE (recirculate blend door)

Sleazy Rider

this is where i lucked out. a po must have been up there at some point. when i popped out the screw and getting ready to tackle the manifold washer, there was none so i was able to just pull the lines apart and remove the controller and wiring harness. i also had a controller out of a 94' and they both looked identical so i took a chance and put the 94 controller in place. also added a small washer and nut to keep things together and started up the car. as luck would have it, a/c came thru the vents immediately and was able to cycle thru the various vents. shut off the car and finished putting everything in its place and put the seat back in.
back to being a happy camper while the outside temps are hovering around the century mark.

Furias15x

Dreaded 96 stuck on heat and defrost.
Decided to tackle this today. All was going well had the controller ready to go back in after about 1.5 hours.
I decided to forgo using the manifold and just hook lines directly to each other.

Get it back together go to check it, I secretly know it wont work that's just how it goes with this POS, now the fan is on full speed and there are no green lights on the buttons. The system won't respond. Yes I have cleaned buttons and they were all working before hand. Now none are lit up and I have this weird thing on the LCD. I held down the fan buttons and it pulled no code.

I did try unplugging and plugging it back in.
What is this? What do I have to do now??







This is all it will do and it comes on full fan speed at Key On. Still blowing out the defrost and floor.

raid007

HI THERE, MY ADVICE TO YOU IS WATCH THE LINK TO SITE VIDEO OF WHERE THE BOX CAN BE SENT FOR REPAIRS, THE ALSO OFFER ELECTRONIC DISPLAY REPAIR SKITS.
GOOD LUCK YOUR WILL BE GLAD TO HAVE ONLY DONE THIS ONCE.
Jack

tvetta

I have read all this post and need some clarity . If you cut the vacuum tubes before the manifold on the programmer to avoid removing that push on nut. Then you directly connect new vacuum lines to the programmer instead of using the manifold. How do you connect the new vacuum lines to the colored lines under the dash? Do you slide a brass tube between them as a transition? Is 3/32" ID the proper size vacuum tubing to use?

Furias15x

You can see in my pics just above how I slide on vacuum over each existing line. It will be this way in the controller and the car. I see what you are saying using a piece of brass. That would be the proper way to do it if the vacuum lines in the car were soft. These are fairly firm and will hold shape with a new line going on top of them. Then I cut away the old manifold and fed them through the original place. I was sure to label them. Once I put the unit back in the car I slid them on each of the lines that were in the car per their color. So there is a little slack in the lines now but not much and working under there really sucks. I am not a big guy, 5'9" 175 and I still had to take the seat and the seat frame out of the car for room. I used 7/64 lines and it was tough to get them on. I used a little lubricant, CRC.

Mtocrs1

Hi Everyone- As a first time Corvette owner I just want to say thank you to all that contributed to this post and to Batee.com. I called Batee to either order the module repair kit or have them perform the repair, instead of just taking my money like allot of venders from my other car platform (Buick GN), they referred me to this post. I took the information from here and got my 96 HVAC working like it should!
My fix was just to trim the rubber nipples on the module connector and reinstall the unit. It only took me 1.5 hours but I was lucky. Someone had been in there before, the retainer clip was already removed and longer bolt and nut were installed. The module had also already been reconditioned. The internals were spotless and the cardboard backer was new and held on by electrical tape. A previous owner probably sold the car because of the issue.....
Before I realized the little connector clip was removed I was thinking there is no way a guy my size can get to the connecter. I started looking for alternatives and thought.... These cars were built on an assembly line, no way the assemblers contorted around to install the vacuum lines and module. My guess is that the module was mounted to the fire wall, next the dash surround. Once the the dash surround was installed the assemblers would connect the HVAC plug to the module. Then finally the dash gauge cluster and trim. My guess is that with the gauge cluster removed from the dash, the HVAC module connectors are easily accessible (or maybe not).
So if this happens to others it might be easier to remove the gauge cluster to access the vacuum line connector but I don't know that for sure. Just something to consider.

silverfoxx

Anyone know off hand what size the fastener is that holds the controller to firewall. Once I'm in there on my back it would be good to know the size tool to take with me. Thanks much.

chaley

If I remember correctly it is a 10mm.

ChumpVette

7mm screw.

silverfoxx

What about the nut that holds the hose connector to the unit? I read where that is not a regular nut.

Schnickiman

Last week I had a local Corvette shop fix the problem of air not blowing out the front vents. The tech replaced the hoses on the programmer. You can see in the top part of the picture what was replaced. It works great now. Nothing like feeling the blast of cool air coming from the front vents on a hot summer. Lived with this problem for many years. Finally fixed. 96 Grand Sport.

96 Corvette AC Programmer. Replaced the original part shown in the upper half of picture with new hoses and connectors.