Midgetfist

Several weeks ago, the HVAC on the '96 began slowing down. First it took 20-30 seconds to transition to the Panel Vents when on AUTO (sound familiar), then taking several minutes, and finally only blowing air from the BI-LEVELS (i.e. defrost & heater). No HVAC codes present.

1. Super cheap fix - Checked the vacuum valve under the right fuel rail cover - perfectly fine.

2. Relatively cheap fix - Removed ECC head unit and opened it up to check for electronic bugs - nothing. Re-installed and made sure the connector was firmly placed.

3. :banghead: fix - Went after the Programmer, which was suspect from the beginning (actually, steps 1 & 2 above reflect complete denial). For those that have never seen one, there is a series of vacuum lines under the dash connected to a small rubber/silicone block. This small block fits over a series of 6-8 rubber nipples on the front of the Programmer. Well, as the dealer wants $698.00 for a remanufactured Programmer, and a forum sponsor wants $182.00, I figured that I may as well take a crack at fixing it myself first.

Upon inspection, the first thing I noted was that the opening of the rubber nipple associated with the Black vacuum line (source) collapsed enough to almost fully restrict air/vacuum flow. I then turned my attention to the inside of the Programmer; all wiring and vacuum lines inside were intact and without obvious damage.

Using a fresh razor blade, I sliced about 1/16 in. off of the offending nipple (Nip/Tuck :p: ), and found the inside to be completely occluded. I then took off another 1/16 in., and still the airway was completely shut. Turning a 3/32 drill bit by hand, I opened up the airway to its appropriate size.

I re-installed the Programmer and fired the Vette up. To my amazement, it works better than any C4 I've ever been in. Switching between the modes (AUTO, HEAT, VENT, etc.) is rapid-fire. "Off" to "AUTO" is nearly instantaneous (DEFROST to VENT and back is instantaneous). GROOVY! :D
:chevy

Lone Ranger

Great post. I have cut, pasted it and added it to my archives :D Prolly come in handy sometime :yesnod:


[Modified by Lone Ranger, 10:03 PM 8/4/2003]

Midgetfist

The repair was so easy. From the posts I've seen regarding slow or non-responsive AC/Heater functions, I suspect that many people have the same problem I did. I'm going to take out my wife's Programmer ('95) and check it out.

While checking prices on re-man Programmers, I found that 1996's have a different number than others. Anybody know what is different about the '96 HVAC Programmer?
:chevy

ShawnZR-1

Tech Tip! Tech Tip! Read all about it!

Seriously, do a tech tip write up, this sounds like a perfect fix!! :cheers:

dizwiz24

Where is the programmer at?

1Patriot

I am glad you were successful in getting you AC running correctly.

I had the same/sim problem with the AC in my 96 and went through similiar steps in am attempt to locate a solution, Well, to be end game, none of the vacumn paths were restricted or defective. The only solution was to replace the AC Programmer Module with a rebuilt unit.

Now, which of the forum sponsors has a unit for $182.00????

Midgetfist

The Last Detail - http://www.tld-corvette.com/index.htm - $182 for a 1996 C68 Programmer (Reman). I thoght they were a sponsor, but now I don't see them listed.

1Patriot

Midgetfist,
Thanks for the info on the part.

BrianCunningham

:iagree: :cheers:

speedracer1996

:cool: Thanks man, I'll have to give that a shot. :D

gbygeorge

Thanks for the info. I will try this in the next day or so. I must admit, thinking of working on the vette is a little intimidating.

LannyL81

I did the "fix" a bit differently....I insert a short piece of tubing in the vacuum connector to keep it from closing. I should have the tubing around here someplace...think I got it from McMaster Carr...had to buy two feet of it and only used about 3" for all the lines.

No more problems...all vents work as they should.

SC300TURBO

Does anyone have a picture of this programer? ...and easiest easy to remove it?...also I'm curious what was showing on your display when you had the problem? ...mine shows one dot and2 dashes .__ like that...and none of the functions work. ..none of the buttons light up...but I can go into the programming mode..very weird. .thank in advance. ..my car is a 1994

HAD2HAV2

eBay sells many years of AC/Heater programmers. Some are used in Cadillac's. Most are located just above the gas pedal.

Silver96ce

The programmer is on the firewall above the gas pedal. Your problem may be with the programmer, the control head (the display unit in the dash) or the connectors. Try disconnecting the battery for thirty seconds to do a reset. If that doesn't work try re-seating the connectors on the programmer and the control head. Failing that you can take apart the control head and clean the connections and buttons internally.

To remove the programmer it is a real pain. I took out the drivers seat, knee bolster and metal plate behind it in order to access the programmer. I also removed the sill cover and speaker to give more room as you have to lay on your back with your head toward the firewall to work to get it out. And even then you have to be a contortionist (or a person that likes pain) to get it out.

HAD2HAV2

Correct, the seat has to go. If all programmers mount the same way, only one 7mm screw holds it to the firewall. If you are lucky, like my 88, you can drop the controller down without laying upside down or taking the steering wheel off. It helps to be looking at a programmer to see how it mounts.

QCVette

I did a similar fix. I used syringe needles (the pink ones from Walgreens). I blunted the ends and cut them the right length. I just inserted them into the nipples and put it together again. The stainless needles will never collapse with vacuum and there is practically no flow, so the ID size is relatively unimportant. It worked great.

(Note: it was actually on my mom's '97 Buick which has a similar design AC programmer. The dealer wanted over $1000 in parts and labor. I fixed it for about $.025 with about a half hour labor. It has been working for over 10 years now.)

pianoguy

Here's a thread with pics:

https://www.corvetteforum.com/forums...l-problem.html

jad9943

The blower motor stopped working abruptly. Following the service manual diagnostic, i am referred to replace the programmer. I can't see how the programmer would abruptly stop the blower motor. I have taken it off before and repaired the vacuum lines and it worked fine. I have no blower at any speed and all the service manual diagnostics are positive except the power from the fan control. Anybody ever run across this? It quit working so quickly it seems electrical.

Jubran Farhat

did you remove the whole programmer off the firewall or just the cover ? Also there are nipples inside and on the outside..did you do them on all or just the ones on the outside?