04Z16

Okay I've asked about this before and now have time to tear into the dash to fix this problem. The A/C programmer I was told is located above the right knee area under the metal plate, is this true for the 96's?? I dropped the panel, took off the metal plate and ...:confused:... Well I sure in the heck didn't see any controller or vacuum harness . The only vacuum line that runs into the car from what I can tell is the one going to the clutch/brake pedals to disengage the cruise control. Any idea's or even if the 96 model is the same as the other years? I would have been nice to get a shop manual for Xmas. Thanks for any help.
Leo

04Z16

Anyone any help?

pablocruise

Sorry, not sur if this does help, but just in case:
http://forums.corvetteforum.com/zerothread?id=202649
Forum is slow rightnow what with the holidays an' all.

grndspt

If need be I can dig out my shop manual. Let me know? Gotta help another GS owner #571 :D

-=Jeff=-

look again.. but this time look above the accelerator pedal.. it is a black box held in with one screw in the center of the bottom and there are 2 tabs at the top that fit in slots in the firewall..

Hope this helps

FrankLT4CE

Jeff is correct the programmer is above the accelerator pedal (I seem to remember about 6 inches above). You will see 5 colored lines running into and out of it. If you remove the knee trim panel above the passengers feet you will also find the main black source vacuum line from the engine along with a convenient connector above the passengers feet where you can do vacuum testing of the main source line. You will also find the orange line running to the recirculate vacuum valve at the far right above the passengers feet. You can disconnect the vacuum line there and test that valve and that vacuum circuit for proper function. FrankLT4CE

89 Bob L

Frank is right on target and Paul pointed you to the correct thread to fix the programmer.

04Z16

Thanks for all the advice, I'm back to the garage to tackle this thing again. I'll post more later on how things went.

C4Cvette

OK, I found my A/C programmer, but cant get the vacume lines disconnected from it to get the unit out of the car. I know there is a clip in the middle of the vacume lines, but how can I get it off? I did however turn it over and see the board inside it. It seems a little more complex than the one on the older C4's.
Please let me know what you find.
:seeya

FrankLT4CE

When I was investigating my car I was never able to disconnect the 5 vacuum connector from the programmer. Instead I was able to disconnect the individual vacuum lines from their vacuum actuators and do my testing there, ie testing both for vacuum to the vacuum actuator with the car running by using the buttons on the AC controller, and also test for actuator function with the engine off by applying vacuum from my hand held vacuum pump to each individual actuator while listening for valve movement. I was able to get at 3 of the 4 vacuum actuators this way without removing the instrument panel. The 4th one is very high in the IP and I can get my fingers on the connection but I believe the only way to get access to it and test it is to remove the instrument panel. Hope this info helps. FrankLT4CE

89 Bob L

in the middle of the vacum line harness is a bolt. You need a deep thin wall socket to remove the bolt, then just pull the harness off.

C4Cvette

On mine it looks like it has a flat round clip in the middle of it. I dont want to be prying on it with a pick to try to get it off because it might damage the vacume lines..

C4Cvette

FrankLT4CE, I know that 2 of the actuators are right at the AC programmer, so taking those lines off is easy. There are 3 heading up to the top center of the dash that I can not find where they go. I had the radio, AC controls and the information cluster, but couldnt seem to trace them down. I think the lines were Brown and Orange. You said 1goes behind the IC, any ideas about the other 2?
:seeya

phrogs

Thats what mine has on it I pulled it off with a pair of needle nose pliers I had to get in there upside down but it thats no big deal for me get in there and work on it and it will come off...

04Z16

Okay, got into mine today and found I have vacumm coming into the programmer but it is not switching to anything other than the Defrost and Heater. The controller seems to check out okay and doesn't give any codes. Must be one of the components on the programmer board. I'm off all this week and will just mess around with it and see what I can find out.

FrankLT4CE

C4CVette, I'm not sure if our 94 vs 96 are the same color codes. On my 96 pink is for the rear mode valve, which I believe operates the center vent; dark blue is for the front mode valve, which I believe is for the heater outlet; orange is for the recirculate mode valve; and tan is for the defroster mode valve.

I was able to disconnect the lines from the vacuum actuators, except for the case of the tan - defroster. By removing the programmer bolt and swinging the programmer out of the way I could get my fingers on the tan line at the defroster vacuum actuator but because it is so high up in the IP I could not remove it to test there. I tried many approaches , as you did, and my conclusion is that the only way to get to it is to remove the whole IP. (Also see my post to 96 GrandSport.) FrankLT4CE

FrankLT4CE

96GrandSport, To give you a little more info from my 96, I seem to have found that my programmer and controller are ok, but I'm not 100 % positive. There are no controller codes when I went thru the controller diagnostics, but I recently found my defroster did not work in cold weather. I have not checked for controller codes since I discovered this.

I found I have manifold vacuum at the black source line at the passenger feet area. Also I have manifold vacuum going to each of the vacuum actuators when I push in the appropriate button on the controller ie, pink rear mode valve when heater button is pushed;
dark blue front mode valve when vent button is pushed;
orange recirc mode valve when recirc button is pushed.
So for this reason I believe my controller and programmer are probably ok.

When I apply vacuum to the 3 vacuum actuators that I can reach ,ie orange, blue, and pink I have found that orange recirc clearly works good. I can hear some valve movement with the blue front mode valve, and some movement with the pink rear mode valve, so I think I may have a problem with the 2 valves possibly. I could not test the tan defroster mode valve.

When I have used a vacuum jumper line from the black source line to the following vacuum actuators I got the following results:
to orange - activates recirc clearly
to blue - no effect- meaning front mode valve is no good or stuck
to pink - causes heater vents to work 60 %, defroster 35%, side defrosters 5% - meaning rear mode is possibly ok, but also the rear mode valve is suppose to control the center vent where I have no flow of air ????
So I think I may have a bad vacuum actuator(s) or a stuck valve(s) ????
I've read that many other 96's had problems with bad controllers.
Thats as far as I got in my investigation. Its very cold at my house now. I'm waiting for warmer weather before I do more. Hope this info may help someone else. Let me know what you guys find on your cars. FrankLT4CE

FrankLT4CE

Oops, when I said my defroster didn't work in cold weather I meant to say the rear glass defroster (wires in rear glass).

04Z16

Thanks for all the information Frank, it's gotten cold down here also. I might heat the garage and play with it some more tomorrow, depends on what the wife wants to do it's her first day off in a while. So far with mine it is pointing towards a bad programmer board . When I apply vacumm to lines I can get the vents to shift but not from the push buttons. I do believe the board to be bad. I have a different board coming and might just wait for it to get here and mess around with it some more. If the new board fixes the problem then it will be time to play on the bench and find out how this thing really works. I'll post more when I dig back into to it again. Thanks again for all information and help.

P.S.
Any luck on your rear defroster? Do you have 12 volts back to the glass??